Phrase reversals
You are encouraged to solve this task according to the task description, using any language you may know.
- Task
Given a string of space separated words containing the following phrase:
rosetta code phrase reversal
- Reverse the characters of the string.
- Reverse the characters of each individual word in the string, maintaining original word order within the string.
- Reverse the order of each word of the string, maintaining the order of characters in each word.
Show your output here.
- See also
AutoHotkey
<lang AutoHotKey>var = ( Rosetta Code Phrase Reversal )
array := strsplit(var, " ")
loop, % array.maxindex() string .= array[array.maxindex() - A_index + 1] . " "
loop, % array.maxindex() { m := array[A_index] array2 := strsplit(m, "") Loop, % array2.maxindex() string2 .= array2[array2.maxindex() - A_index + 1] string2 .= " " }
array := strsplit(string, " " )
loop, % array.maxindex() { m := array[A_index] array3 := strsplit(m, "") Loop, % array3.maxindex() string3 .= array3[array3.maxindex() - A_index + 1] string3 .= " " }
MsgBox % var . "`n" . string3 . "`n" . String . "`n" . string2 ExitApp
esc::ExitApp</lang>
- Output:
Rosetta Code Phrase Reversal lasreveR esarhP edoC attesoR Reversal Phrase Code Rosetta attesoR edoC esarhP lasreveR
Ada
To split a string into words, the package "Simple_Parse" from another task [[1]] is used.
<lang Ada><with Ada.Text_IO, Simple_Parse;
procedure Phrase_Reversal is
function Reverse_String (Item : String) return String is
Result : String (Item'Range);
begin
for I in Item'range loop
Result (Result'Last - I + Item'First) := Item (I);
end loop;
return Result;
end Reverse_String;
function Reverse_Words(S: String) return String is
Cursor: Positive := S'First;
Word: String := Simple_Parse.Next_Word(S, Cursor);
begin
if Cursor > S'Last then -- Word holds the last word
return Reverse_String(Word);
else
return Reverse_String(Word) & " " & Reverse_Words(S(Cursor .. S'Last));
end if;
end Reverse_Words;
function Reverse_Order(S: String) return String is
Cursor: Positive := S'First;
Word: String := Simple_Parse.Next_Word(S, Cursor);
begin
if Cursor > S'Last then -- Word holds the last word
return Word;
else
return Reverse_Order(S(Cursor .. S'Last)) & " " & Word;
end if; end Reverse_Order; Phrase: String := "rosetta code phrase reversal"; use Ada.Text_IO;
begin
Put_Line("0. The original phrase: """ & Phrase & """");
Put_Line("1. Reverse the entire phrase: """ & Reverse_String(Phrase) & """");
Put_Line("2. Reverse words, same order: """ & Reverse_Words(Phrase) & """");
Put_Line("2. Reverse order, same words: """ & Reverse_Order(Phrase) & """");
end Phrase_Reversal;</lang>
- Output:
0. The original phrase: "rosetta code phrase reversal" 1. Reverse the entire phrase: "lasrever esarhp edoc attesor" 2. Reverse words, same order: "attesor edoc esarhp lasrever" 2. Reverse order, same words: "reversal phrase code rosetta"
ALGOL 68
<lang algol68># reverses the characters in str from start pos to end pos # PROC in place reverse = ( REF STRING str, INT start pos, INT end pos )VOID:
BEGIN
INT fpos := start pos, epos := end pos;
WHILE fpos < epos
DO
CHAR c := str[ fpos ];
str[ fpos ] := str[ epos ];
str[ epos ] := c;
fpos +:= 1;
epos -:= 1
OD
END; # in place reverse #
STRING original phrase := "rosetta code phrase reversal";
STRING whole reversed := original phrase; in place reverse( whole reversed, LWB whole reversed, UPB whole reversed );
- reverse the individual words #
STRING words reversed := original phrase; INT start pos := LWB words reversed;
WHILE
# skip leading spaces #
WHILE IF start pos <= UPB words reversed
THEN words reversed[ start pos ] = " "
ELSE FALSE
FI
DO start pos +:= 1
OD;
start pos <= UPB words reversed
DO
# have another word, find it #
INT end pos := start pos;
WHILE IF end pos <= UPB words reversed
THEN words reversed[ end pos ] /= " "
ELSE FALSE
FI
DO end pos +:= 1
OD;
in place reverse( words reversed, start pos, end pos - 1 );
start pos := end pos + 1
OD;
- reversing the reversed words in the same order as the original will #
- reverse the order of the words #
STRING order reversed := words reversed; in place reverse( order reversed, LWB order reversed, UPB order reversed );
print( ( original phrase, ": whole reversed -> ", whole reversed, newline
, original phrase, ": words reversed -> ", words reversed, newline
, original phrase, ": order reversed -> ", order reversed, newline
)
)</lang>
- Output:
rosetta code phrase reversal: whole reversed -> lasrever esarhp edoc attesor rosetta code phrase reversal: words reversed -> attesor edoc esarhp lasrever rosetta code phrase reversal: order reversed -> reversal phrase code rosetta
AppleScript
AppleScript has a very small and patchy library of primitive functions. To accumulate a larger and more coherent library, which includes some higher order functions, we can try to overcome two architectural weaknesses: 1. Built-in functions have a different type from user functions, and 2. user functions are second class properties of (first class) script objects.
Here is a simple illustration of unifying (and elevating) the function type by wrapping the built-in functions in user handlers (perhaps making some of them polymorphic where needed), and also obtaining first class status for ordinary user handler functions by 'lifting' them (for use as arguments in higher order functions) into a first class script object. (This process can be inlined, or abstracted out to an mReturn or mInject function).
<lang AppleScript>-- REVERSED PHRASES, COMPONENT WORDS, AND WORD ORDER ---------------------
-- reverseString, reverseEachWord, reverseWordOrder :: String -> String on stringReverse(s)
|reverse|(s)
end stringReverse
on reverseEachWord(s)
wordLevel(curry(my map)'s |λ|(my |reverse|))'s |λ|(s)
end reverseEachWord
on reverseWordOrder(s)
wordLevel(my |reverse|)'s |λ|(s)
end reverseWordOrder
-- wordLevel :: ([String] -> [String]) -> String -> String
on wordLevel(f)
script
on |λ|(x)
unwords(mReturn(f)'s |λ|(|words|(x)))
end |λ|
end script
end wordLevel
-- TEST ----------------------------------------------------------------------
on run
unlines(|<*>|({stringReverse, reverseEachWord, reverseWordOrder}, ¬
{"rosetta code phrase reversal"}))
-->
-- "lasrever esarhp edoc attesor
-- attesor edoc esarhp lasrever
-- reversal phrase code rosetta"
end run
-- GENERIC FUNCTIONS ---------------------------------------------------------
-- A list of functions applied to a list of arguments -- (<*> | ap) :: [(a -> b)] -> [a] -> [b] on |<*>|(fs, xs)
set {nf, nx} to {length of fs, length of xs}
set acc to {}
repeat with i from 1 to nf
tell mReturn(item i of fs)
repeat with j from 1 to nx
set end of acc to |λ|(contents of (item j of xs))
end repeat
end tell
end repeat
return acc
end |<*>|
-- curry :: (Script|Handler) -> Script on curry(f)
script
on |λ|(a)
script
on |λ|(b)
|λ|(a, b) of mReturn(f)
end |λ|
end script
end |λ|
end script
end curry
-- intercalate :: Text -> [Text] -> Text on intercalate(strText, lstText)
set {dlm, my text item delimiters} to {my text item delimiters, strText}
set strJoined to lstText as text
set my text item delimiters to dlm
return strJoined
end intercalate
-- map :: (a -> b) -> [a] -> [b] on map(f, xs)
tell mReturn(f)
set lng to length of xs
set lst to {}
repeat with i from 1 to lng
set end of lst to |λ|(item i of xs, i, xs)
end repeat
return lst
end tell
end map
-- Lift 2nd class handler function into 1st class script wrapper -- mReturn :: Handler -> Script on mReturn(f)
if class of f is script then
f
else
script
property |λ| : f
end script
end if
end mReturn
-- reverse :: [a] -> [a] on |reverse|(xs)
if class of xs is text then
(reverse of characters of xs) as text
else
reverse of xs
end if
end |reverse|
-- words :: String -> [String] on |words|(s)
words of s
end |words|
-- unlines :: [String] -> String on unlines(lstLines)
intercalate(linefeed, lstLines)
end unlines
-- unwords :: [String] -> String on unwords(lstWords)
intercalate(space, lstWords)
end unwords</lang>
- Output:
"lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta"
AWK
<lang awk># Usage: awk -f phrase_revers.awk function rev(s, del, n,i,a,r) {
n = split(s, a, del)
r = a[1]
for(i=2; i <= n; i++) {r = a[i] del r }
return r
}
BEGIN {
p0 = "Rosetta Code Phrase Reversal"
fmt = "%-20s: %s\n" printf( fmt, "input", p0 ) printf( fmt, "string reversed", rev(p0, "") ) wr = rev(p0, " ") printf( fmt, "word-order reversed", wr ) printf( fmt, "each word reversed", rev(wr) )
}</lang>
- Output:
input : Rosetta Code Phrase Reversal string reversed : lasreveR esarhP edoC attesoR word-order reversed : Reversal Phrase Code Rosetta each word reversed : attesoR edoC esarhP lasreveR
BaCon
<lang qbasic>phrase$ = "rosetta code phrase reversal"
PRINT REVERSE$(phrase$)
PRINT REV$(REVERSE$(phrase$))
PRINT REV$(phrase$)</lang>
- Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
Batch File
<lang dos>@echo off setlocal enabledelayedexpansion %=== The Main Thing... ===% set "inp=Rosetta Code phrase reversal" call :reverse_string "!inp!" rev1 call :reverse_order "!inp!" rev2 call :reverse_words "!inp!" rev3 cls echo.Original: !inp! echo.Reversed: !rev1! echo.Reversed Order: !rev2! echo.Reversed Words: !rev3! pause>nul exit /b 0 %=== /The Main Thing... ===%
%=== Reverse the Order Function ===%
- reverse_order
set var1=%2 set %var1%=&set word=&set str1=%1
- process1
for /f "tokens=1,*" %%A in (%str1%) do (set str1=%%B&set word=%%A) set %var1%=!word! !%var1%!&set str1="!str1!" if not !str1!=="" goto process1 goto :EOF %=== /Reverse the Order Function ===%
%=== Reverse the Whole String Function ===%
- reverse_string
set var2=%2 set %var2%=&set cnt=0&set str2=%~1
- process2
set char=!str2:~%cnt%,1!&set %var2%=!char!!%var2%! if not "!char!"=="" set /a cnt+=1&goto process2 goto :EOF %=== /Reverse the Whole String Function ===%
%=== Reverse each Words Function ===%
- reverse_words
set var3=%2 set %var3%=&set word=&set str3=%1
- process3
for /f "tokens=1,*" %%A in (%str3%) do (set str3=%%B&set word=%%A) call :reverse_string "%word%" revs set %var3%=!%var3%! !revs!&set str3="!str3!" if not !str3!=="" goto process3 set %var3%=!%var3%:~1,1000000! goto :EOF %=== /Reverse each Words Function ===%</lang>
- Output:
Original: Rosetta Code phrase reversal Reversed: lasrever esarhp edoC attesoR Reversed Order: reversal phrase Code Rosetta Reversed Words: attesoR edoC esarhp lasrever
Bracmat
This example only works correctly with strings only consisting of byte-sized characters. <lang bracmat>( "rosetta code phrase reversal":?text & rev$!text:?output1 & get$(!text,MEM):?words & :?output2:?output3 & whl
' ( !words:%?word %?words & !output2 rev$!word " ":?output2 & " " !word !output3:?output3 )
& str$(!output2 rev$!words):?output2 & str$(!words !output3):?output3 & out
$ ( str
$ ("0:\"" !text "\"\n1:\"" !output1 "\"\n2:\"" !output2 "\"\n3:\"" !output3 \"\n)
)
);</lang> Output:
0:"rosetta code phrase reversal" 1:"lasrever esarhp edoc attesor" 2:"attesor edoc esarhp lasrever" 3:"reversal phrase code rosetta"
C
Working with C strings is often long-winded. <lang C>
- include <stdio.h>
- include <string.h>
/* The functions used are destructive, so after each call the string needs
* to be copied over again. One could easily allocate new strings as * required, but this way allows the caller to manage memory themselves */
char* reverse_section(char *s, size_t length) {
if (length == 0) return s;
size_t i; char temp;
for (i = 0; i < length / 2 + 1; ++i)
temp = s[i], s[i] = s[length - i], s[length - i] = temp;
return s;
}
char* reverse_words_in_order(char *s, char delim) {
if (!strlen(s)) return s;
size_t i, j;
for (i = 0; i < strlen(s) - 1; ++i) {
for (j = 0; s[i + j] != 0 && s[i + j] != delim; ++j)
;
reverse_section(s + i, j - 1);
s += j;
}
return s;
}
char* reverse_string(char *s) {
return strlen(s) ? reverse_section(s, strlen(s) - 1) : s;
}
char* reverse_order_of_words(char *s, char delim) {
reverse_string(s); reverse_words_in_order(s, delim); return s;
}
int main(void) {
char str[] = "rosetta code phrase reversal"; size_t lenstr = sizeof(str) / sizeof(str[0]); char scopy[lenstr]; char delim = ' ';
/* Original String */
printf("Original: \"%s\"\n", str);
/* Reversed string */
strncpy(scopy, str, lenstr);
reverse_string(scopy);
printf("Reversed: \"%s\"\n", scopy);
/* Reversed words in string */
strncpy(scopy, str, lenstr);
reverse_words_in_order(scopy, delim);
printf("Reversed words: \"%s\"\n", scopy);
/* Reversed order of words in string */
strncpy(scopy, str, lenstr);
reverse_order_of_words(scopy, delim);
printf("Reversed order: \"%s\"\n", scopy);
return 0;
} </lang>
- Output:
Original: "rosetta code phrase reversal" Reversed: "lasrever esarhp edoc attesor" Reversed words: "attesor edoc esarhp lasrever" Reversed order: "reversal phrase code rosetta"
C++
<lang cpp>#include <iostream>
- include <iostream>
- include <vector>
- include <algorithm>
- include <string>
- include <iterator>
- include <sstream>
int main() {
std::string s = "rosetta code phrase reversal";
std::cout << "Input : " << s << '\n'
<< "Input reversed : " << std::string(s.rbegin(), s.rend()) << '\n' ;
std::istringstream is(s);
std::vector<std::string> words(std::istream_iterator<std::string>(is), {});
std::cout << "Each word reversed : " ;
for(auto w : words)
std::cout << std::string(w.rbegin(), w.rend()) << ' ';
std::cout << '\n'
<< "Original word order reversed : " ;
reverse_copy(words.begin(), words.end(), std::ostream_iterator<std::string>(std::cout, " "));
std::cout << '\n' ;
} </lang>
- Output:
Input : rosetta code phrase reversal Input reversed : lasrever esarhp edoc attesor Each word reversed : attesor edoc esarhp lasrever Original word order reversed : reversal phrase code rosetta
C#
<lang csharp>using System; using System.Linq; namespace ConsoleApplication {
class Program
{
static void Main(string[] args)
{
//Reverse() is an extension method on IEnumerable<char>.
//The constructor takes a char[], so we have to call ToArray()
Func<string, string> reverse = s => new string(s.Reverse().ToArray());
string phrase = "rosetta code phrase reversal";
//Reverse the string
Console.WriteLine(reverse(phrase));
//Reverse each individual word in the string, maintaining original string order.
Console.WriteLine(string.Join(" ", phrase.Split(' ').Select(word => reverse(word))));
//Reverse the order of each word of the phrase, maintaining the order of characters in each word.
Console.WriteLine(string.Join(" ", phrase.Split(' ').Reverse()));
}
}
}</lang>
Clojure
<lang clojure>(use '[clojure.string :only (join split)]) (def phrase "rosetta code phrase reversal") (defn str-reverse [s] (apply str (reverse s)))
- Reverse string
(str-reverse phrase)
- Words reversed
(join " " (map str-reverse (split phrase #" ")))
- Word order reversed
(apply str (interpose " " (reverse (split phrase #" ")))) </lang>
- Output:
"lasrever esarhp edoc attesor" "attesor edoc esarhp lasrever" "reversal phrase code rosetta"
COBOL
<lang COBOL>
program-id. phra-rev.
data division.
working-storage section.
1 phrase pic x(28) value "rosetta code phrase reversal".
1 wk-str pic x(16).
1 binary.
2 phrase-len pic 9(4).
2 pos pic 9(4).
2 cnt pic 9(4).
procedure division.
compute phrase-len = function length (phrase)
display phrase
display function reverse (phrase)
perform display-words
move function reverse (phrase) to phrase
perform display-words
stop run
.
display-words.
move 1 to pos
perform until pos > phrase-len
unstring phrase delimited space
into wk-str count in cnt
with pointer pos
end-unstring
display function reverse (wk-str (1:cnt))
with no advancing
if pos < phrase-len
display space with no advancing
end-if
end-perform
display space
.
end program phra-rev.
</lang>
- Output:
rosetta code phrase reversal lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
Common Lisp
<lang lisp> (defun split-string (str)
"Split a string into space separated words including spaces"
(do* ((lst nil)
(i (position-if #'alphanumericp str) (position-if #'alphanumericp str :start j))
(j (when i (position #\Space str :start i)) (when i (position #\Space str :start i))) )
((null j) (nreverse (push (subseq str i nil) lst)))
(push (subseq str i j) lst)
(push " " lst) ))
(defun task (str)
(print (reverse str)) (let ((lst (split-string str))) (print (apply #'concatenate 'string (mapcar #'reverse lst))) (print (apply #'concatenate 'string (reverse lst))) ) nil )
</lang>
- Output:
(task "rosetta code phrase reversal")"lasrever esarhp edoc attesor" "attesor edoc esarhp lasrever" "reversal phrase code rosetta" nil
D
Partially lazy. <lang d>void main() @safe {
import std.stdio, std.range, std.algorithm;
immutable phrase = "rosetta code phrase reversal";
phrase.retro.writeln; // Reversed string.
phrase.splitter.map!retro.joiner(" ").writeln; // Words reversed.
phrase.split.retro.joiner(" ").writeln; // Word order reversed.
}</lang>
- Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
EchoLisp
<lang scheme> (define (string-reverse string)
(list->string (reverse (string->list string))))
(define (task str)
(for-each writeln (list
(string-reverse str)
(string-join (map string-reverse (string-split str )))
(string-join (reverse (string-split str ))))))
(task "rosetta code phrase reversal")
"lasrever esarhp edoc attesor" "attesor edoc esarhp lasrever" "reversal phrase code rosetta"
</lang>
Elena
ELENA 4.x : <lang elena>import extensions; import extensions'text; import system'routines;
public program() {
var reverse := (s => s.toArray().sequenceReverse().summarize(new StringWriter()));
var phrase := "rosetta code phrase reversal";
console.printLine(phrase);
//Reverse the string
console.printLine(reverse(phrase));
//Reverse each individual word in the string, maintaining original string order.
console.printLine(phrase.splitBy:" ".selectBy:(s => reverse(s).add(" ")).summarize(new StringWriter()));
//Reverse the order of each word of the phrase, maintaining the order of characters in each word.
console.printLine(reverse(phrase.splitBy:" ".selectBy:(s => s + " ")))
}</lang>
- Output:
rosetta code phrase reversal lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
Elixir
<lang elixir>str = "rosetta code phrase reversal"
IO.puts String.reverse(str) IO.puts String.split(str) |> Enum.map(&String.reverse(&1)) |> Enum.join(" ") IO.puts String.split(str) |> Enum.reverse |> Enum.join(" ")</lang>
- Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
Emacs Lisp
<lang Emacs Lisp> (defun reverse-sep (words sep)
(mapconcat 'identity (reverse (split-string words sep) ) sep) )
(defun reverse-chars (line)
(reverse-sep line "") )
(defun reverse-words (line)
(reverse-sep line " ") )
(progn
(setq line "rosetta code phrase reversal")
(insert (format "%s\n" (reverse-chars line) ))
(insert (format "%s\n"
(mapconcat 'identity (mapcar #'reverse-chars
(split-string line) ) " ") ))
(insert (format "%s\n" (reverse-words line) )))
</lang>
Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
Factor
<lang factor> USE: splitting
- splitp ( str -- seq ) " " split ;
- printp ( seq -- ) " " join print ;
- reverse-string ( str -- ) reverse print ;
- reverse-words ( str -- ) splitp [ reverse ] map printp ;
- reverse-phrase ( str -- ) splitp reverse printp ;
"rosetta code phrase reversal" [ reverse-string ] [ reverse-words ] [ reverse-phrase ] tri </lang>
- Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
Fortran
The key here is the ability via F90 to specify an array span, as A(first:last:step) where the step can be negative... This facility is not available for CHARACTER variables where only TEXT(first:last) is available - no step is accommodated and TEXT(last:first) evokes nothing rather than a backwards order as in Python. However, one can have an array of CHARACTER*1 variables, and as an array they can be rolled bidirectionally. For convenience in initialising such an array, EQUIVALENCE(TEXT,ATXT) means that a normal multi-character text literal can be assigned to TEXT via the DATA statement, rather than having to specify the ATXT elements one at a time.
By identifying the first and last character position of each word in TEXT (or equivalently, their indices in ATXT) and storing them in arrays IST and LST, the i'th word can be fingered via IST(i) to LST(i) and of course a DO-loop can step in either direction.
F90 allows a WHILE-loop, and writing something like <lang Fortran> DO WHILE (L1.LE.L .AND. ATXT(L1).LE." ")
L1 = L1 + 1
END DO</lang>
Would be rather more structured and involve fewer GO TOs and their labels, but alas, modern Fortran specifies that there is no specification as to whether or not both terms of an expression such as (A and B) will always be evaluated or instead there will be a shortcut: if A is false then the B term is ignored. And here, the A term checks whether or not L1 is within bounds and if it is not, then the B term should not be evaluated, not just because of the waste of effort but because to do so might involve accessing outside the definition of ATXT. As when the scan chases through the trailing spaces. One could make the array one longer, or rather, L = LEN(TEXT) - 1 for this case but that would be messy, require explanation, be easily forgotten, and, typical ad-hoc testing would be unlikely to detect the mistake.
Alternatively, a GO TO can be removed from view by using EXIT in its place: <lang Fortran> DO L1 = L1,L
IF (ATXT(L1).GT." ") EXIT
END DO</lang> Except that this relies on the index variable retaining its value on exiting the loop, either as fingering the first non-blank or, being L + 1. This expectation is frowned upon in some quarters.
Both variants would have to be followed by a test such as IF (L1 .LE. L) THEN to identify whether the start of a word has been found that would require further processing. So, all in all, suck up the GO TOs...<lang Fortran> PROGRAM REVERSER !Just fooling around.
CHARACTER*(66) TEXT !Holds the text. Easily long enough.
CHARACTER*1 ATXT(66) !But this is what I play with.
EQUIVALENCE (TEXT,ATXT) !Same storage, different access abilities..
DATA TEXT/"Rosetta Code Phrase Reversal"/ !Easier to specify this for TEXT.
INTEGER IST(6),LST(6) !Start and stop positions.
INTEGER N,L,I !Counters.
INTEGER L1,L2 !Fingers for the scan.
CHARACTER*(*) AS,RW,FW,RO,FO !Now for some cramming.
PARAMETER (AS = "Words ordered as supplied") !So that some statements can fit on a line.
PARAMETER (RW = "Reversed words, ", FW = "Forward words, ")
PARAMETER (RO = "reverse order", FO = "forward order")
Chop the text into words.
N = 0 !No words found.
L = LEN(TEXT) !Multiple trailing spaces - no worries.
L2 = 0 !Syncopation: where the previous chomp ended.
10 L1 = L2 !Thus, where a fresh scan should follow.
11 L1 = L1 + 1 !Advance one.
IF (L1.GT.L) GO TO 20 !Finished yet?
IF (ATXT(L1).LE." ") GO TO 11 !No. Skip leading spaces.
L2 = L1 !Righto, L1 is the first non-blank.
12 L2 = L2 + 1 !Scan through the non-blanks.
IF (L2.GT.L) GO TO 13 !Is it safe to look?
IF (ATXT(L2).GT." ") GO TO 12 !Yes. Speed through non-blanks.
13 N = N + 1 !Righto, a word is found in TEXT(L1:L2 - 1)
IST(N) = L1 !So, recall its first character.
LST(N) = L2 - 1 !And its last.
IF (L2.LT.L) GO TO 10 !Perhaps more text follows.
Chuck the words around.
20 WRITE (6,21) N,TEXT !First, say what has been discovered. 21 FORMAT (I4," words have been isolated from the text ",A,/)
WRITE (6,22) AS, (" ",ATXT(IST(I):LST(I):+1), I = 1,N,+1)
WRITE (6,22) RW//RO,(" ",ATXT(LST(I):IST(I):-1), I = N,1,-1)
WRITE (6,22) FW//RO,(" ",ATXT(IST(I):LST(I):+1), I = N,1,-1)
WRITE (6,22) RW//FO,(" ",ATXT(LST(I):IST(I):-1), I = 1,N,+1)
22 FORMAT (A36,":",66A1)
END</lang>
With F77 such array spans can't be used, but all that is necessary is to supply a second implied DO-loop in the WRITE statement, for example <lang Fortran> WRITE (6,22) RW//RO,(" ",(ATXT(J), J = LST(I),IST(I),-1), I = 1,N,+1)</lang>
And the output is...
4 words have been isolated from the text Rosetta Code Phrase Reversal
Words ordered as supplied: Rosetta Code Phrase Reversal
Reversed words, reverse order: lasreveR esarhP edoC attesoR
Forward words, reverse order: Reversal Phrase Code Rosetta
Reversed words, forward order: attesoR edoC esarhP lasreveR
FreeBASIC
<lang freebasic>' FB 1.05.0 Win64
Sub split (s As Const String, sepList As Const String, result() As String)
If s = "" OrElse sepList = "" Then
Redim result(0)
result(0) = s
Return
End If
Dim As Integer i, j, count = 0, empty = 0, length
Dim As Integer position(Len(s) + 1)
position(0) = 0
For i = 0 To len(s) - 1
For j = 0 to Len(sepList) - 1
If s[i] = sepList[j] Then
count += 1
position(count) = i + 1
End If
Next j
Next i
Redim result(count)
If count = 0 Then
result(0) = s
Return
End If
position(count + 1) = len(s) + 1
For i = 1 To count + 1
length = position(i) - position(i - 1) - 1
result(i - 1) = Mid(s, position(i - 1) + 1, length)
Next
End Sub
Function reverse(s As Const String) As String
If s = "" Then Return "" Dim t As String = s Dim length As Integer = Len(t) For i As Integer = 0 to length\2 - 1 Swap t[i], t[length - 1 - i] Next Return t
End Function
Dim s As String = "rosetta code phrase reversal" Dim a() As String Dim sepList As String = " "
Print "Original string => "; s Print "Reversed string => "; reverse(s) Print "Reversed words => "; split s, sepList, a() For i As Integer = LBound(a) To UBound(a)
Print reverse(a(i)); " ";
Next Print Print "Reversed order => "; For i As Integer = UBound(a) To LBound(a) Step -1
Print a(i); " ";
Next Print : Print Print "Press any key to quit" Sleep</lang>
- Output:
Original string => rosetta code phrase reversal Reversed string => lasrever esarhp edoc attesor Reversed words => attesor edoc esarhp lasrever Reversed order => reversal phrase code rosetta
Gambas
Click this link to run this code <lang gambas>Public Sub Main() Dim sString As String = "rosetta code phrase reversal" 'The string Dim sNewString, sTemp As String 'String variables Dim siCount As Short 'Counter Dim sWord As New String[] 'Word store
For siCount = Len(sString) DownTo 1 'Loop backwards through the string
sNewString &= Mid(sString, sicount, 1) 'Add each character to the new string
Next
Print "Original string = \t" & sString & "\n" & 'Print the original string
"Reversed string = \t" & sNewString 'Print the reversed string
sNewString = "" 'Reset sNewString
For Each sTemp In Split(sString, " ") 'Split the original string by the spaces
sWord.Add(sTemp) 'Add each word to sWord array
Next
For siCount = sWord.max DownTo 0 'Loop backward through each word in sWord
sNewString &= sWord[siCount] & " " 'Add each word to to sNewString
Next
Print "Reversed word order = \t" & sNewString 'Print reversed word order
sNewString = "" 'Reset sNewString For Each sTemp In sWord 'For each word in sWord
For siCount = Len(sTemp) DownTo 1 'Loop backward through the word sNewString &= Mid(sTemp, siCount, 1) 'Add the characters to sNewString Next sNewString &= " " 'Add a space at the end of each word
Next
Print "Words reversed = \t" & sNewString 'Print words reversed
End</lang> Output:
Original string = rosetta code phrase reversal Reversed string = lasrever esarhp edoc attesor Reversed word order = reversal phrase code rosetta Words reversed = attesor edoc esarhp lasrever
Go
Simple
<lang go>package main
import ( "fmt" "strings" )
const phrase = "rosetta code phrase reversal"
func revStr(s string) string { rs := make([]rune, len(s)) i := len(s) for _, r := range s { i-- rs[i] = r } return string(rs[i:]) }
func main() { fmt.Println("Reversed: ", revStr(phrase))
ws := strings.Fields(phrase) for i, w := range ws { ws[i] = revStr(w) } fmt.Println("Words reversed: ", strings.Join(ws, " "))
ws = strings.Fields(phrase) last := len(ws) - 1 for i, w := range ws[:len(ws)/2] { ws[i], ws[last-i] = ws[last-i], w } fmt.Println("Word order reversed:", strings.Join(ws, " ")) }</lang>
- Output:
Reversed: lasrever esarhp edoc attesor Words reversed: attesor edoc esarhp lasrever Word order reversed: reversal phrase code rosetta
Alternative
<lang go>package main
import ( "fmt" "regexp" "sort" "strings" )
const phrase = "rosetta code phrase reversal"
type reversible interface { Len() int Swap(i, j int) }
func reverse(p reversible) { mid := p.Len() / 2 last := p.Len() - 1 for i := 0; i < mid; i++ { p.Swap(i, last-i) } }
type runeSlice []rune
func (p runeSlice) Len() int { return len(p) } func (p runeSlice) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
func reverseString(s string) string { r := runeSlice(s) reverse(r) return string(r) }
var rx = regexp.MustCompile(`\S*`)
func reverseWords(s string) string { return rx.ReplaceAllStringFunc(s, func(m string) string { return reverseString(m) }) }
func reverseWordOrder(s string) string { l := sort.StringSlice(strings.Fields(s)) reverse(l) return strings.Join(l, " ") }
func main() { fmt.Println("Reversed: ", reverseString(phrase)) fmt.Println("Words reversed: ", reverseWords(phrase)) fmt.Println("Word order reversed:", reverseWordOrder(phrase)) }</lang>
- Output:
Reversed: lasrever esarhp edoc attesor Words reversed: attesor edoc esarhp lasrever Word order reversed: reversal phrase code rosetta
Groovy
<lang groovy>def phaseReverse = { text, closure -> closure(text.split(/ /)).join(' ')}
def text = 'rosetta code phrase reversal' println "Original: $text" println "Reversed: ${phaseReverse(text) { it.reverse().collect { it.reverse() } } }" println "Reversed Words: ${phaseReverse(text) { it.collect { it.reverse() } } }" println "Reversed Order: ${phaseReverse(text) { it.reverse() } }"</lang>
- Output:
Original: rosetta code phrase reversal Reversed: lasrever esarhp edoc attesor Reversed Words: attesor edoc esarhp lasrever Reversed Order: reversal phrase code rosetta
Haskell
<lang haskell>reverseString, reverseEachWord, reverseWordOrder :: String -> String reverseString = reverse
reverseEachWord = wordLevel (fmap reverse)
reverseWordOrder = wordLevel reverse
wordLevel :: ([String] -> [String]) -> String -> String wordLevel f = unwords . f . words
main :: IO () main =
(putStrLn . unlines) $ [reverseString, reverseEachWord, reverseWordOrder] <*> ["rosetta code phrase reversal"]</lang>
- Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
IS-BASIC
<lang IS-BASIC>100 PROGRAM "ReverseS.bas" 110 LET S$="Rosetta Code Pharse Reversal" 120 PRINT S$ 130 PRINT REVERSE$(S$) 140 PRINT REVERSEW$(S$) 150 PRINT REVERSEC$(S$) 160 DEF REVERSE$(S$) 170 LET T$="" 180 FOR I=LEN(S$) TO 1 STEP-1 190 LET T$=T$&S$(I) 200 NEXT 210 LET REVERSE$=T$ 220 END DEF 230 DEF REVERSEW$(S$) 240 LET T$="":LET PE=LEN(S$) 250 FOR PS=PE TO 1 STEP-1 260 IF PS=1 OR S$(PS)=" " THEN LET T$=T$&" ":LET T$=T$<RIM$(S$(PS:PE)):LET PE=PS-1 270 NEXT 280 LET REVERSEW$=LTRIM$(T$) 290 END DEF 300 DEF REVERSEC$(S$) 310 LET T$="":LET PS=1 320 FOR PE=1 TO LEN(S$) 330 IF PE=LEN(S$) OR S$(PE)=" " THEN LET T$=T$&" ":LET T$=T$&REVERSE$(RTRIM$(S$(PS:PE))):LET PS=PE+1 340 NEXT 350 LET REVERSEC$=LTRIM$(T$) 360 END DEF</lang>
J
Solution: <lang j> getWords=: (' '&splitstring) :. (' '&joinstring)
reverseString=: |. reverseWords=: |.&.>&.getWords reverseWordOrder=: |.&.getWords</lang>
Usage: <lang j> phrase=: 'rosetta code phrase reversal'
(reverseWordOrder , reverseWords ,: reverseString) phrase
reversal phrase code rosetta attesor edoc esarhp lasrever lasrever esarhp edoc attesor</lang>
Java
<lang java5>import java.util.Arrays;
public class PhraseRev{ private static String reverse(String x){ return new StringBuilder(x).reverse().toString(); }
private static <T> T[] reverse(T[] x){ T[] rev = Arrays.copyOf(x, x.length); for(int i = x.length - 1; i >= 0; i--){ rev[x.length - 1 - i] = x[i]; } return rev; }
private static String join(String[] arr, String joinStr){ StringBuilder joined = new StringBuilder(); for(int i = 0; i < arr.length; i++){ joined.append(arr[i]); if(i < arr.length - 1) joined.append(joinStr); } return joined.toString(); }
public static void main(String[] args){ String str = "rosetta code phrase reversal";
System.out.println("Straight-up reversed: " + reverse(str)); String[] words = str.split(" "); for(int i = 0; i < words.length; i++){ words[i] = reverse(words[i]); } System.out.println("Reversed words: " + join(words, " ")); System.out.println("Reversed word order: " + join(reverse(str.split(" ")), " ")); } }</lang>
- Output:
Straight-up reversed: lasrever esarhp edoc attesor Reversed words: attesor edoc esarhp lasrever Reversed word order: reversal phrase code rosetta
JavaScript
ES5
<lang JavaScript>(function (p) {
return [ p.split().reverse().join(),
p.split(' ').map(function (x) {
return x.split().reverse().join();
}).join(' '),
p.split(' ').reverse().join(' ')
].join('\n');
})('rosetta code phrase reversal');</lang>
- Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
ES6
<lang JavaScript>(() => {
'use strict'
// reverseString, reverseEachWord, reverseWordOrder :: String -> String
const
reverseString = s => reverse(s),
reverseEachWord = s => wordLevel(map(reverse))(s),
reverseWordOrder = s => wordLevel(reverse)(s);
// wordLevel :: ([String] -> [String]) -> String -> String
const wordLevel = f =>
x => unwords(f(words(x)));
// GENERIC FUNCTIONS -----------------------------------------------------
// A list of functions applied to a list of arguments
// <*> :: [(a -> b)] -> [a] -> [b]
const ap = (fs, xs) => //
[].concat.apply([], fs.map(f => //
[].concat.apply([], xs.map(x => [f(x)]))));
// 2 or more arguments
// curry :: Function -> Function
const curry = (f, ...args) => {
const go = xs => xs.length >= f.length ? (f.apply(null, xs)) :
function () {
return go(xs.concat(Array.from(arguments)));
};
return go([].slice.call(args, 1));
};
// map :: (a -> b) -> [a] -> [b] const map = curry((f, xs) => xs.map(f));
// reverse :: [a] -> [a]
const reverse = curry(xs =>
typeof xs === 'string' ? (
xs.split()
.reverse()
.join()
) : xs.slice(0)
.reverse());
// unlines :: [String] -> String
const unlines = xs => xs.join('\n');
// unwords :: [String] -> String
const unwords = xs => xs.join(' ');
// words :: String -> [String] const words = s => s.split(/\s+/);
// TEST ------------------------------------------------------------------
return unlines(
ap([
reverseString,
reverseEachWord,
reverseWordOrder
], ["rosetta code phrase reversal"])
);
})();</lang>
- Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
jq
<lang jq>def reverse_string: explode | reverse | implode;
"rosetta code phrase reversal" | split(" ") as $words | "0. input: \(.)",
"1. string reversed: \(reverse_string)",
"2. each word reversed: \($words | map(reverse_string) | join(" "))",
"3. word-order reversed: \($words | reverse | join(" "))"</lang>
- Output:
$ jq -r -n -f Phrase_reversals.jq 0. input: rosetta code phrase reversal 1. string reversed: lasrever esarhp edoc attesor 2. each word reversed: attesor edoc esarhp lasrever 3. word-order reversed: reversal phrase code rosetta
Julia
<lang Julia> s = "rosetta code phrase reversal"
println("The original phrase.") println(" ", s)
println("Reverse the string.") t = reverse(s) println(" ", t)
println("Reverse each individual word in the string.") t = join(map(reverse, split(s, " ")), " ") println(" ", t)
println("Reverse the order of each word of the phrase.") t = join(reverse(split(s, " ")), " ") println(" ", t) </lang>
- Output:
The original phrase. rosetta code phrase reversal Reverse the string. lasrever esarhp edoc attesor Reverse each individual word in the string. attesor edoc esarhp lasrever Reverse the order of each word of the phrase. reversal phrase code rosetta
K
<lang K> / Rosetta code phrase reversal / phraserev.k
reversestr: {|x} getnxtwd: {c:(&" "~'x); if[c~!0;w::x;:""];w::c[0]#x; x: ((1+c[0]) _ x)} revwords: {rw:""; while[~(x~""); x: getnxtwd x;rw,:|w;rw,:" "];:-1 _ rw} revwordorder: {rw:""; while[~(x~""); x: getnxtwd x;rw:" ",rw;rw:w,rw];:-1 _ rw}
</lang> The output of a session is given below:
- Output:
K Console - Enter \ for help \l phraserev phrase: "rosetta code phrase reversal" "rosetta code phrase reversal" reversestr phrase "lasrever esarhp edoc attesor" revwords phrase "attesor edoc esarhp lasrever" revwordorder phrase "reversal phrase code rosetta"
Kotlin
<lang scala>// version 1.0.6
fun reverseEachWord(s: String) = s.split(" ").map { it.reversed() }.joinToString(" ")
fun main(args: Array<String>) {
val original = "rosetta code phrase reversal"
val reversed = original.reversed()
println("Original string => $original")
println("Reversed string => $reversed")
println("Reversed words => ${reverseEachWord(original)}")
println("Reversed order => ${reverseEachWord(reversed)}")
}</lang>
- Output:
Original string => rosetta code phrase reversal Reversed string => lasrever esarhp edoc attesor Reversed words => attesor edoc esarhp lasrever Reversed order => reversal phrase code rosetta
Lua
<lang Lua>-- Return a copy of table t in which each string is reversed function reverseEach (t)
local rev = {}
for k, v in pairs(t) do rev[k] = v:reverse() end
return rev
end
-- Return a reversed copy of table t function tabReverse (t)
local revTab = {}
for i, v in ipairs(t) do revTab[#t - i + 1] = v end
return revTab
end
-- Split string str into a table on space characters function wordSplit (str)
local t = {}
for word in str:gmatch("%S+") do table.insert(t, word) end
return t
end
-- Main procedure local str = "rosetta code phrase reversal" local tab = wordSplit(str) print("1. " .. str:reverse()) print("2. " .. table.concat(reverseEach(tab), " ")) print("3. " .. table.concat(tabReverse(tab), " "))</lang>
- Output:
1. lasrever esarhp edoc attesor 2. attesor edoc esarhp lasrever 3. reversal phrase code rosetta
Maple
<lang Maple>#reverse the string str := "rosetta code phrase reversal": print(StringTools:-Reverse(str)):
- reverse each word
lst := convert(StringTools:-Split(str, " "), Array): for i to numelems(lst) do lst[i] := StringTools:-Reverse(lst[i]): end do: print(StringTools:-Join(convert(lst,list)," ")):
- reverse word order
print(StringTools:-Join(ListTools:-Reverse(StringTools:-Split(str," ")), " ")):</lang>
- Output:
"lasrever esarhp edoc attesor"
"attesor edoc esarhp lasrever"
"reversal phrase code rosetta"
Mathematica / Wolfram Language
<lang Mathematica>phrase = "Rosetta Code Phrase Reversal";
reverseWords[phrase_String] :=
StringJoin @@ Riffle[Reverse@StringSplit@phrase, " "]
reverseLetters[phrase_String] :=
StringJoin @@ Riffle[Map[StringJoin @@ Reverse[Characters@#] &, StringSplit@phrase], " "]
{phrase, reverseWords@phrase, reverseLetters@phrase,
reverseWords@reverseLetters@phrase} // TableForm</lang>
- Output:
Rosetta Code Phrase Reversal Reversal Phrase Code Rosetta attesoR edoC esarhP lasreveR lasreveR esarhP edoC attesoR
MiniScript
<lang MiniScript>phrase = "rosetta code phrase reversal"
// general sequence reversal function reverse = function(seq)
out = []
for i in range(seq.len-1, 0)
out.push seq[i]
end for
if seq isa string then return out.join("")
return out
end function
// 1. Reverse the characters of the string. print reverse(phrase)
// 2. Reverse the characters of each individual word in the string, maintaining original word order within the string. words = phrase.split for i in words.indexes
words[i] = reverse(words[i])
end for print words.join
// 3. Reverse the order of each word of the string, maintaining the order of characters in each word. print reverse(phrase.split).join </lang>
- Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
MUMPS
<lang MUMPS>set string="Rosetta Code Phrase Reversal" set str="",len=$length(string," ") for i=1:1:len set $piece(str," ",i)=$piece(string," ",len-i+1) write string,! write $reverse(string),! write str,! write $reverse(str),!</lang>
- Output:
Rosetta Code Phrase ReversallasreveR esarhP edoC attesoR Reversal Phrase Code Rosetta attesoR edoC esarhP lasreveR
Oforth
<lang Oforth>"rosetta code phrase reversal" reverse println "rosetta code phrase reversal" words map(#reverse) unwords println "rosetta code phrase reversal" words reverse unwords println</lang>
- Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
Perl
<lang perl>use feature 'say'; my $s = "rosetta code phrase reversal";
say "0. Input : ", $s; say "1. String reversed : ", scalar reverse $s; say "2. Each word reversed : ", join " ", reverse split / /, reverse $s; say "3. Word-order reversed : ", join " ", reverse split / /,$s;
- Or, using a regex:
say "2. Each word reversed : ", $s =~ s/[^ ]+/reverse $&/gre;</lang>
- Output:
0. Input : rosetta code phrase reversal 1. String reversed : lasrever esarhp edoc attesor 2. Each word reversed : attesor edoc esarhp lasrever 3. Word-order reversed : reversal phrase code rosetta 2. Each word reversed : attesor edoc esarhp lasrever
Perl 6
<lang perl6>my $s = 'rosetta code phrase reversal';
put 'Input : ', $s; put 'String reversed : ', $s.flip; put 'Each word reversed : ', $s.words».flip; put 'Word-order reversed : ', $s.words.reverse;</lang>
- Output:
Input : rosetta code phrase reversal String reversed : lasrever esarhp edoc attesor Each word reversed : attesor edoc esarhp lasrever Word-order reversed : reversal phrase code rosetta
Phix
I have assumed step 2 should be applied to the result of step 1, and step 3 applied to the result of step 2.
Obviously I'm right and everyone else is wrong!
<lang Phix>constant test="rosetta code phrase reversal"
?reverse(test)
sequence words = split(reverse(test))
for i=1 to length(words) do
words[i] = reverse(words[i])
end for ?join(words) ?join(reverse(words))</lang>
- Output:
"lasrever esarhp edoc attesor" "reversal phrase code rosetta" "rosetta code phrase reversal"
Phixmonti
<lang Phixmonti>"Rosetta Code Phrase Reversal" dup print nl
dup reverse print nl
split dup reverse len for . head print " " print tail nip endfor . nl
len for drop head reverse print " " print tail nip endfor drop</lang>
PHP
<lang php><?php // Initialize a variable with the input desired $strin = "rosetta code phrase reversal";
// Show user what original input was echo "Input: ".$strin."\n";
// Show the full input reversed echo "Reversed: ".strrev($strin)."\n";
// reverse the word letters in place $str_words_reversed = ""; $temp = explode(" ", $strin); foreach($temp as $word) $str_words_reversed .= strrev($word)." ";
// Show the reversed words in place echo "Words reversed: ".$str_words_reversed."\n";
// reverse the word order while leaving the words in order
$str_word_order_reversed = "";
$temp = explode(" ", $strin);
for($i=(count($temp)-1); $i>=0; $i--)
$str_word_order_reversed .= $temp[$i]." ";
// Show the reversal of the word order while leaving the words in order echo "Word order reversed: ".$str_word_order_reversed."\n"; </lang>
Input: rosetta code phrase reversal Reversed: lasrever esarhp edoc attesor Words reversed: attesor edoc esarhp lasrever Word order reversed: reversal phrase code rosetta
PicoLisp
<lang PicoLisp>(let (S (chop "rosetta code phrase reversal") L (split S " "))
(prinl (reverse S)) (prinl (glue " " (mapcar reverse L))) (prinl (glue " " (reverse L))) )</lang>
Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
PL/I
<lang PL/I> reverser: procedure options (main); /* 19 August 2015 */
declare (phrase, r, word) character (100) varying; declare (start, end) fixed binary;
phrase = 'rosetta code phrase reversal';
put ('The original phrase is: ' || phrase);
put skip list ( '1. ' || reverse(phrase) );
start = 1; r = ; put skip edit ('2. ') (a);
do until ( end > length(phrase) );
end = index(phrase, ' ', start); /* Find end of the next word.*/
if end = 0 then end = length(phrase) + 1; /* We're at the last word. */
word = substr(phrase, start, end-start);
put edit ( reverse(word), ' ' ) (a); /* Append reversed word. */
r = word || ' ' || r; /* Prepend normal word. */
start = end+1;
end;
put skip list ('3. ' || r);
end reverser; </lang> Output:
The original phrase is: rosetta code phrase reversal 1. lasrever esarhp edoc attesor 2. attesor edoc esarhp lasrever 3. reversal phrase code rosetta
Plain TeX
<lang tex>\def\afterfi#1#2\fi{#2\fi#1} \def\RevSingleWord#1{\RevSingleWordi{}#1\RSWA\RSWB\RSWB\RSWB\RSWB\RSWB\RSWB\RSWB\RSWB\RSWA} \def\RevSingleWordi#1#2#3#4#5#6#7#8#9{\RSWgobtoB#9\RSWend\RSWB\RevSingleWordi{#9#8#7#6#5#4#3#2#1}} \def\RSWend\RSWB\RevSingleWordi#1#2\RSWA{\RSWgobtoA#1} \def\RSWgobtoA#1\RSWA{}\def\RSWgobtoB#1\RSWB{} %--- \def\firstchartonil#1#2\nil{#1} \def\RevOrderSameWords#1{\RevOrderSameWordsi{}#1 \. \* \* \* \* \* \* \* \* \.} \def\RevOrderSameWordsi#1#2 #3 #4 #5 #6 #7 #8 #9 {% \expandafter\ifx\expandafter\*\firstchartonil#9\nil \expandafter\ROSWend\else\expandafter\RevOrderSameWordsi\fi{#9 #8 #7 #6 #5 #4 #3 #2#1}% } \def\ROSWend#1#2\.{\ROSWendi#1} \def\ROSWendi#1\.{\romannumeral-`\-} %--- \def\ROWquark{\ROWquark} \def\RevOnlyWords#1{\edef\ROWtemp{\noexpand\RevOnlyWordsi{}#1 \noexpand\ROWquark\space}\ROWtemp} \def\RevOnlyWordsi#1#2 {% \ifx\ROWquark#2\afterfi{\ROWgoblastspace#1\nil}% \else\afterfi{\RevOnlyWordsi{#1\RevSingleWord{#2} }}% \fi } \def\ROWgoblastspace#1 \nil{#1} %--- \def\RevAll#1{\RevAlli{}#1 \. \* \* \* \* \* \* \* \* \.\:} \def\RevAlli#1#2 #3 #4 #5 #6 #7 #8 #9 {% \expandafter\ifx\expandafter\*\firstchartonil#9\nil \expandafter\RAWend\else\expandafter\RevAlli\fi{#9 #8 #7 #6 #5 #4 #3 #2#1}% } \def\RAWend#1#2\.{\RAWendi#1} \def\RAWendi#1\.{\expandafter\RAWendii\romannumeral-`\-} \def\RAWendii#1\:{\RevOnlyWords{#1}} %-- \halign{#\hfil: &#\cr Initial&rosetta code phrase reversal\cr Reverse all&\RevAll{rosetta code phrase reversal}\cr Reverse order, same words&\RevOrderSameWords{rosetta code phrase reversal}\cr Reverse only words&\RevOnlyWords{rosetta code phrase reversal}\cr\crcr} \bye</lang>
pdf or dvi output looks like:
Initial : rosetta code phrase reversal Reverse all : lasrever esarhp edoc attesor Reverse order, same words: reversal phrase code rosetta Reverse only words : attesor edoc esarhp lasrever
PowerShell
<lang PowerShell> function reverse($a, $sep = "") {
if($a.Length -gt 0) {
$a = $a[($a.Length -1)..0] -join $sep
}
$a
} $line = "rosetta code phrase reversal" $task1 = reverse $line $task2 = ($line -split " " | foreach{ reverse $_ }) -join " " $task3 = reverse ($line -split " ") " " $task1 $task2 $task3
</lang>
Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
PureBasic
<lang PureBasic>#TEXT="rosetta code phrase reversal"
If OpenConsole("rosetta code phrase reversal")
Define idx.i=1, txt.s=""
Print(~"Original:\t\t")
PrintN(#TEXT)
Print(~"Reversed:\t\t")
PrintN(ReverseString(#TEXT))
Print(~"Reversed words:\t\t")
txt=StringField(#TEXT,idx," ")
While Len(txt)
Print(ReverseString(txt)+" ")
idx+1
txt=StringField(#TEXT,idx," ")
Wend
PrintN("")
Print(~"Reversed order:\t\t")
idx-1
txt=StringField(#TEXT,idx," ")
While Len(txt)
Print(txt+" ")
If idx>1 : idx-1 : Else : Break : EndIf
txt=StringField(#TEXT,idx," ")
Wend
Input()
EndIf</lang>
- Output:
Original: rosetta code phrase reversal Reversed: lasrever esarhp edoc attesor Reversed words: attesor edoc esarhp lasrever Reversed order: reversal phrase code rosetta
Python
These examples use the extended slicing notation of [::-1] to reverse strings and lists of strings:
<lang python>>>> phrase = "rosetta code phrase reversal"
>>> phrase[::-1] # Reversed.
'lasrever esarhp edoc attesor'
>>> ' '.join(word[::-1] for word in phrase.split()) # Words reversed.
'attesor edoc esarhp lasrever'
>>> ' '.join(phrase.split()[::-1]) # Word order reversed.
'reversal phrase code rosetta'
>>> </lang>
Or, variously composing three reusable abstractions – reverse, words, and unwords:
<lang python>String reversals at different levels.
- reversedCharacters :: String -> String
def reversedCharacters(s):
All characters in reversed sequence. return reverse(s)
- wordsWithReversedCharacters :: String -> String
def wordsWithReversedCharacters(s):
Characters within each word in reversed sequence. return unwords(map(reverse, words(s)))
- reversedWordOrder :: String -> String
def reversedWordOrder(s):
Sequence of words reversed. return unwords(reverse(words(s)))
- TESTS -------------------------------------------------
- main :: IO()
def main():
Tests
s = 'rosetta code phrase reversal'
print(
tabulated(s + ':\n')(
lambda f: f.__name__
)(lambda s: "'" + s + "'")(
lambda f: f(s)
)([
reversedCharacters,
wordsWithReversedCharacters,
reversedWordOrder
])
)
- GENERIC -------------------------------------------------
- compose (<<<) :: (b -> c) -> (a -> b) -> a -> c
def compose(g):
Function composition. return lambda f: lambda x: g(f(x))
- reverse :: [a] -> [a]
- reverse :: String -> String
def reverse(xs):
The elements of xs in reverse order.
return xs[::-1] if isinstance(xs, str) else (
list(reversed(xs))
)
- tabulated :: String -> (a -> String) ->
- (b -> String) ->
- (a -> b) -> [a] -> String
def tabulated(s):
Heading -> x display function -> fx display function ->
f -> value list -> tabular string.
def go(xShow, fxShow, f, xs):
w = max(map(compose(len)(xShow), xs))
return s + '\n' + '\n'.join(
xShow(x).rjust(w, ' ') + ' -> ' + fxShow(f(x)) for x in xs
)
return lambda xShow: lambda fxShow: lambda f: lambda xs: go(
xShow, fxShow, f, xs
)
- unwords :: [String] -> String
def unwords(xs):
A space-separated string derived from a list of words. return ' '.join(xs)
- words :: String -> [String]
def words(s):
A list of words delimited by characters
representing white space.
return s.split()
if __name__ == '__main__':
main()</lang>
- Output:
rosetta code phrase reversal:
reversedCharacters -> 'lasrever esarhp edoc attesor'
wordsWithReversedCharacters -> 'attesor edoc esarhp lasrever'
reversedWordOrder -> 'reversal phrase code rosetta'
Racket
<lang racket>#lang racket/base (require
(only-in srfi/13 string-reverse) (only-in racket/string string-split string-join))
(define (phrase-reversal s)
(list (string-reverse s) (string-join (map string-reverse (string-split s))) (string-join (reverse (string-split s)))))
(for-each displayln (phrase-reversal "rosetta code phrase reversal"))</lang>
- Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
REXX
version 1
Working with REXX (strings and words) is trivial. <lang rexx>s='rosetta code phrase reversal' r1=reverse(s) r2= Do i=1 To words(s)
r2=r2 reverse(word(s,i)) End
r2=strip(r2) r3= Do i=words(s) To 1 By -1
r3=r3 word(s,i) End
r3=strip(r3) Say "input : " s say "string reversed : " r1 say "each word reversed : " r2 say "word-order reversed : " r3</lang>
- Output:
input : rosetta code phrase reversal string reversed : lasrever esarhp edoc attesor each word reversed : attesor edoc esarhp lasrever word-order reversed : reversal phrase code rosetta
version 2
<lang rexx>/*REXX program reverses words and also letters in a string in various (several) ways. */ parse arg $ /*obtain optional arguments from the CL*/ if $= then $= "rosetta code phrase reversal" /*Not specified? Then use the default.*/ L=; W= /*initialize two REXX variables to null*/
do j=1 for words($); _= word($, j) /*extract each word in the $ string. */
L= L reverse(_); W= _ W /*reverse letters; reverse words. */
end /*j*/
say ' the original phrase used: ' $ say ' original phrase reversed: ' reverse($) say ' reversed individual words: ' strip(L) say ' reversed words in phrases: ' W /*stick a fork in it, we're all done. */</lang>
- output when using the default input string:
the original phrase used: rosetta code phrase reversal original phrase reversed: lasrever esarhp edoc attesor reversed individual words: attesor edoc esarhp lasrever reversed words in phrases: reversal phrase code rosetta
Ring
<lang ring> aString = "Welcome to the Ring Language" bString = "" see reverseString(aString)
func reverseString cString
for i= len(cString) to 1 step -1
bString = bString + cString[i]
next
return bString
</lang>
Output:
egaugnaL gniR eht ot emocleW
Ruby
<lang ruby>str = "rosetta code phrase reversal"
puts str.reverse # Reversed string. puts str.split.map(&:reverse).join(" ") # Words reversed. puts str.split.reverse.join(" ") # Word order reversed.</lang>
- Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
Scala
<lang scala>object PhraseReversals extends App {
val phrase = scala.io.StdIn.readLine
println(phrase.reverse)
println(phrase.split(' ').map(_.reverse).mkString(" "))
println(phrase.split(' ').reverse.mkString(" "))
}</lang>
- Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
Seed7
<lang seed7>$ include "seed7_05.s7i";
const proc: main is func
local
var string: phrase is "rosetta code phrase reversal";
var string: word is "";
var array string: wordList is 0 times "";
begin
writeln("The original phrase:" rpad 27 <& phrase);
writeln("Reverse the entire phrase:" rpad 27 <& reverse(phrase));
for word range split(phrase, ' ') do
wordList &:= reverse(word);
end for;
writeln("Reverse words, same order:" rpad 27 <& join(wordList, ' '));
wordList := 0 times "";
for word range split(phrase, ' ') do
wordList := [] (word) & wordList;
end for;
writeln("Reverse order, same words:" rpad 27 <& join(wordList, ' '));
end func;</lang>
- Output:
The original phrase: rosetta code phrase reversal Reverse the entire phrase: lasrever esarhp edoc attesor Reverse words, same order: attesor edoc esarhp lasrever Reverse order, same words: reversal phrase code rosetta
Sidef
<lang ruby>var str = "rosetta code phrase reversal";
say str.reverse; # reversed string say str.words.map{.reverse}.join(' '); # words reversed say str.words.reverse.join(' '); # word order reversed</lang>
- Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
Swift
<lang swift> func reverseString(s:String)->String{
var temp = [Character]()
for i in s.characters{
temp.append(i)
}
var j=s.characters.count-1
for i in s.characters{
temp[j]=i
j-=1
}
return String(temp)
}
func reverseWord(s:String)->String{
var temp = [Character]()
var result:String=""
for i in s.characters{
if i==" "{
result += "\(reverseString(s:String(temp))) "
temp=[Character]()
}
else {
temp.append(i)
}
if i==s[s.index(before: s.endIndex)]{
result += (reverseString(s:String(temp)))
}
}
return result
}
func flipString(s:String)->String{
return reverseWord(s:reverseString(s:s))
} print(str) print(reverseString(s:str)) print(reverseWord(s:str)) print(flipString(s:str)) </lang>
Tcl
<lang tcl>set s "rosetta code phrase reversal"
- Reverse all characters
puts [string reverse $s]
- Reverse characters in each word
puts [lmap word $s {string reverse $word}]
- Reverse the words but not the characters
puts [lreverse $s]</lang>
- Output:
lasrever esarhp edoc attesor attesor edoc esarhp lasrever reversal phrase code rosetta
UNIX Shell
Version 1
Requires "rev" command.
<lang sh>s1="rosetta code phrase reversal" echo "Original string ----------------------> "$s1
echo -n "1.) Reverse the string ---------------> " echo $s1|rev
echo -n "2.) Reverse characters of each word --> " echo $s1|tr " " "\n"|rev|tr "\n" " ";echo
echo -n "3.) Reverse word order ---------------> " word_num=$(echo $s1|wc -w) while [ $word_num != 0 ];do echo -n $(echo $s1|cut -d " " -f $word_num);echo -n " " word_num=$(expr $word_num - 1);done;echo</lang>
- Output:
Original string ----------------------> rosetta code phrase reversal 1.) Reverse the string ---------------> lasrever esarhp edoc attesor 2.) Reverse characters of each word --> attesor edoc esarhp lasrever 3.) Reverse word order ---------------> reversal phrase code rosetta
Version 2
Does not require "rev" command.
<lang sh>s1="rosetta code phrase reversal" echo "Original string --> "$s1
echo -n "1.) Reverse the string --> " length=$(echo $s1|wc -c) while [ $length != 0 ];do echo $s1|cut -c$length|tr -d "\n" length=$(expr $length - 1) done;echo
echo -n "2.) Reverse characters of each word --> " word_quantity=$(echo $s1|wc -w) word_quantity=$(expr $word_quantity + 1) word_num=1 while [ $word_num != $word_quantity ];do length=$(echo $s1|cut -d " " -f $word_num|wc -c) while [ $length != 0 ];do echo $s1|cut -d " " -f $word_num|cut -c$length|tr -d "\n" length=$(expr $length - 1);done;echo -n " " word_num=$(expr $word_num + 1);done;echo
echo -n "3.) Reverse word order --> " word_num=$(echo $s1|wc -w) while [ $word_num != 0 ];do echo -n $(echo $s1|cut -d " " -f $word_num);echo -n " " word_num=$(expr $word_num - 1);done;echo</lang>
- Output:
Original string --> rosetta code phrase reversal 1.) Reverse the string --> lasrever esarhp edoc attesor 2.) Reverse characters of each word --> attesor edoc esarhp lasrever 3.) Reverse word order --> reversal phrase code rosetta
VBA
<lang vb> Option Explicit
Sub Main_Phrase_Reversals() Const PHRASE As String = "rosetta code phrase reversal"
Debug.Print "Original String : " & PHRASE Debug.Print "Reverse String : " & Reverse_String(PHRASE) Debug.Print "Reverse each individual word : " & Reverse_each_individual_word(PHRASE) Debug.Print "Reverse order of each word : " & Reverse_the_order_of_each_word(PHRASE)
End Sub
Function Reverse_String(strPhrase As String) As String
Reverse_String = StrReverse(strPhrase)
End Function
Function Reverse_each_individual_word(strPhrase As String) As String Dim Words, i&, strTemp$
Words = Split(strPhrase, " ")
For i = 0 To UBound(Words)
Words(i) = Reverse_String(CStr(Words(i)))
Next i
Reverse_each_individual_word = Join(Words, " ")
End Function
Function Reverse_the_order_of_each_word(strPhrase As String) As String Dim Words, i&, strTemp$
Words = Split(strPhrase, " ")
For i = UBound(Words) To 0 Step -1
strTemp = strTemp & " " & Words(i)
Next i
Reverse_the_order_of_each_word = Trim(strTemp)
End Function </lang>
- Output:
Original String : rosetta code phrase reversal Reverse String : lasrever esarhp edoc attesor Reverse each individual word : attesor edoc esarhp lasrever Reverse order of each word : reversal phrase code rosetta
VBScript
<lang vb> Phrase = "rosetta code phrase reversal"
WScript.StdOut.Write "Original String : " & Phrase WScript.StdOut.WriteLine WScript.StdOut.Write "Reverse String : " & RevString(Phrase) WScript.StdOut.WriteLine WScript.StdOut.Write "Reverse String Each Word : " & RevStringEachWord(Phrase) WScript.StdOut.WriteLine WScript.StdOut.Write "Reverse Phrase : " & RevPhrase(Phrase) WScript.StdOut.WriteLine
Function RevString(s) x = Len(s) For i = 1 To Len(s) RevString = RevString & Mid(s,x,1) x = x - 1 Next End Function
Function RevStringEachWord(s) arr = Split(s," ") For i = 0 To UBound(arr) RevStringEachWord = RevStringEachWord & RevString(arr(i)) If i < UBound(arr) Then RevStringEachWord = RevStringEachWord & " " End If Next End Function
Function RevPhrase(s) arr = Split(s," ") For i = UBound(arr) To LBound(arr) Step -1 RevPhrase = RevPhrase & arr(i) If i > LBound(arr) Then RevPhrase = RevPhrase & " " End If Next End Function </lang>
- Output:
Original String : rosetta code phrase reversal Reverse String : lasrever esarhp edoc attesor Reverse String Each Word : attesor edoc esarhp lasrever Reverse Phrase : reversal phrase code rosetta
Yabasic
<lang Yabasic>phrase$ = "Rosetta Code Phrase Reversal"
dim word$(1)
n = token(phrase$, word$())
print phrase$
for i = n to 1 step -1
print reverse$(word$(i)), " ";
next
for i = n to 1 step -1
print word$(i), " ";
next
for i = 1 to n
print reverse$(word$(i)), " ";
next
sub reverse$(w$)
local i, rw$
for i = len(w$) to 1 step -1
rw$ = rw$ + mid$(w$, i, 1)
next
return rw$
end sub</lang>
zkl
<lang zkl>zkl: var str="rosetta code phrase reversal" rosetta code phrase reversal
zkl: str.reverse() #1 lasrever esarhp edoc attesor
zkl: str.split().apply("reverse").concat(" ") #2 string to list to string attesor edoc esarhp lasrever
zkl: str.split().reverse().concat(" ") #3 reversal phrase code rosetta</lang>
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