Phrase reversals

Phrase reversals is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Given a string of space separated words containing the following phrase:

"rosetta code phrase reversal"

1. Reverse the string.
2. Reverse each individual word in the string, maintaining original string order.
3. Reverse the order of each word of the phrase, maintaining the order of characters in each word.

Show your output here.

See also Reverse a string, Reverse words in a string

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

D

Partially lazy. <lang d>void main() {

   import std.stdio, std.range;

   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

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

Java

Works with: Java version 1.5+

<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

Python

<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(word for word in phrase.split()[::-1]) # Word order reversed. 'reversal phrase code rosetta' >>> </lang>