Determine if a string has all unique characters
- Task
Given a character string (which may be empty, or have a length of zero characters):
- create a function/procedure/routine to:
- determine if all the characters in the string are unique
- indicate if or which character is duplicated and where
- display each string and it's length (as the strings are being examined)
- a zero─length (empty) string shall be considered as unique
- process the strings from left─to─right
- if unique, display a message saying such
- if not unique, then:
- display a message saying such
- display what character is duplicated
- only the 1st non─unique character need be displayed
- display where "both" duplicated characters are in the string
- the above messages can be part of a single message
- display the hexadecimal value of the duplicated character
Use (at least) these five test values (strings):
- a string of length 0 (an empty string)
- a string of length 1 which is a single period (.)
- a string of length 6 which contains: abcABC
- a string of length 7 which contains a blank in the middle: XYZ ZYX
- a string of length 36 which doesn't contain the letter "oh":
- 1234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ
Show all output here on this page.
- Related task
Factor
<lang factor>USING: accessors formatting generalizations io kernel math.parser regexp sequences sets strings ;
- >dup-char< ( str n -- char hex first-index second-index )
1string tuck [ dup first >hex ] 2dip <regexp> all-matching-slices first2 [ from>> ] bi@ ;
- duplicate-info. ( str -- )
dup duplicates [ >dup-char< "'%s' (0x%s) at indices %d and %d.\n" printf ] with each nl ;
- uniqueness-report. ( str -- )
dup dup length "%u — length %d — contains " printf dup all-unique? [ drop "all unique characters." print nl ] [ "duplicate characters:" print duplicate-info. ] if ;
"" "." "abcABC" "XYZ ZYX" "1234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ" [ uniqueness-report. ] 5 napply</lang>
- Output:
"" — length 0 — contains all unique characters. "." — length 1 — contains all unique characters. "abcABC" — length 6 — contains all unique characters. "XYZ ZYX" — length 7 — contains duplicate characters: 'Z' (0x5a) at indices 2 and 4. 'Y' (0x59) at indices 1 and 5. 'X' (0x58) at indices 0 and 6. "1234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ" — length 36 — contains duplicate characters: '0' (0x30) at indices 9 and 24.
Go
<lang go>package main
import "fmt"
func analyze(s string) {
// maps each character to a slice of the indices it occurs at charMap := make(map[rune][]int) runes := []rune(s) for i, c := range runes { charMap[c] = append(charMap[c], i) } le := len(runes) fmt.Printf("Analyzing %q which has a length of %d:\n", s, le) if len(charMap) == le { fmt.Println(" All characters in the string are unique.\n") } else { fmt.Println(" The following characters are duplicated:-") for k, v := range charMap { if len(v) > 1 { fmt.Printf(" %q (%#x) at indices %v\n", k, k, v) } } fmt.Println() }
}
func main() {
strings := []string{ "", ".", "abcABC", "XYZ ZYX", "1234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ", "hétérogénéité", "😍😀🙌💃😍🙌", "🐠🐟🐡🦈🐬🐳🐋🐡", } for _, s := range strings { analyze(s) }
}</lang>
- Output:
Analyzing "" which has a length of 0: All characters in the string are unique. Analyzing "." which has a length of 1: All characters in the string are unique. Analyzing "abcABC" which has a length of 6: All characters in the string are unique. Analyzing "XYZ ZYX" which has a length of 7: The following characters are duplicated:- 'X' (0x58) at indices [0 6] 'Y' (0x59) at indices [1 5] 'Z' (0x5a) at indices [2 4] Analyzing "1234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ" which has a length of 36: The following characters are duplicated:- '0' (0x30) at indices [9 24] Analyzing "hétérogénéité" which has a length of 13: The following characters are duplicated:- 'é' (0xe9) at indices [1 3 7 9 12] 't' (0x74) at indices [2 11] Analyzing "😍😀🙌💃😍🙌" which has a length of 6: The following characters are duplicated:- '😍' (0x1f60d) at indices [0 4] '🙌' (0x1f64c) at indices [2 5] Analyzing "🐠🐟🐡🦈🐬🐳🐋🐡" which has a length of 8: The following characters are duplicated:- '🐡' (0x1f421) at indices [2 7]
Perl 6
Perl 6 works with unicode natively and handles combining characters and multi-byte emoji correctly. In the last string, notice the the length is correctly shown as 11 characters and that the delta with a combining circumflex in position 6 is not the same as the deltas without in positions 5 & 9.
<lang perl6> -> $str {
print "\n{$str.perl} (length: {$str.chars}), has "; if my $match = $str.match( / (.).*$0 /, :ex ) { my %m; %m{.values.Str}.append(flat 1 + .from, .pos) for $match.list; say "duplicated characters:"; say "'{.key}' ({.key.uninames}; hex ordinal: {(.key.ords).fmt: "0x%X"})" ~ " in positions: {.value.sort.squish.join: ', '}" for %m.sort( *.value[0] ); } else { say "no duplicated characters." }
} for
, '.', 'abcABC', 'XYZ ZYX', '1234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ', '01234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ0X', '🦋🙂👨👩👧👦🙄ΔΔ̂ 🦋Δ👍👨👩👧👦'</lang>
- Output:
"" (length: 0), has no duplicated characters. "." (length: 1), has no duplicated characters. "abcABC" (length: 6), has no duplicated characters. "XYZ ZYX" (length: 7), has duplicated characters: 'X' (LATIN CAPITAL LETTER X; hex ordinal: 0x58) in positions: 1, 7 'Y' (LATIN CAPITAL LETTER Y; hex ordinal: 0x59) in positions: 2, 6 'Z' (LATIN CAPITAL LETTER Z; hex ordinal: 0x5A) in positions: 3, 5 "1234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ" (length: 36), has duplicated characters: '0' (DIGIT ZERO; hex ordinal: 0x30) in positions: 10, 25 "01234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ0X" (length: 39), has duplicated characters: '0' (DIGIT ZERO; hex ordinal: 0x30) in positions: 1, 11, 26, 38 'X' (LATIN CAPITAL LETTER X; hex ordinal: 0x58) in positions: 35, 39 "🦋🙂👨👩👧👦🙄ΔΔ̂ 🦋Δ👍👨👩👧👦" (length: 11), has duplicated characters: '🦋' (BUTTERFLY; hex ordinal: 0x1F98B) in positions: 1, 8 '👨👩👧👦' (MAN ZERO WIDTH JOINER WOMAN ZERO WIDTH JOINER GIRL ZERO WIDTH JOINER BOY; hex ordinal: 0x1F468 0x200D 0x1F469 0x200D 0x1F467 0x200D 0x1F466) in positions: 3, 11 'Δ' (GREEK CAPITAL LETTER DELTA; hex ordinal: 0x394) in positions: 5, 9
REXX
<lang rexx>/*REXX pgm determines if a string is comprised of all unique characters (no duplicates).*/ @.= /*assign a default for the @. array. */ parse arg @.1 /*obtain optional argument from the CL.*/ if @.1= then do; @.1= /*Not specified? Then assume defaults.*/
@.2= . @.3= 'abcABC' @.4= 'XYZ ZYX' @.5= '1234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ' end
do j=1; if j\==1 & @.j== then leave /*String is null & not j=1? We're done*/ say copies('─', 79) /*display a separator line (a fence). */ say 'Testing for the string (length' length(@.j)"): " @.j say dup= isUnique(@.j) say 'The characters in the string' word("are aren't", 1 + (dup>0) ) 'all unique.' if dup==0 then iterate ?= substr(@.j, dup, 1) say 'The character ' ? " ('"c2x(?)"'x) at position " dup , ' is repeated at position ' pos(?, @.j, dup+1) end /*j*/
exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ isUnique: procedure; parse arg x /*obtain the character string.*/
do k=1 to length(x) - 1 /*examine all but the last. */ p= pos( substr(x, k, 1), x, k + 1) /*see if the Kth char is a dup*/ if p\==0 then return k /*Find a dup? Return location.*/ end /*k*/ return 0 /*indicate all chars unique. */</lang>
- output when using the internal defaults
─────────────────────────────────────────────────────────────────────────────── Testing for the string (length 0): The characters in the string are all unique. ─────────────────────────────────────────────────────────────────────────────── Testing for the string (length 1): . The characters in the string are all unique. ─────────────────────────────────────────────────────────────────────────────── Testing for the string (length 6): abcABC The characters in the string are all unique. ─────────────────────────────────────────────────────────────────────────────── Testing for the string (length 7): XYZ ZYX The characters in the string aren't all unique. The character X ('58'x) at position 1 is repeated at position 7 ─────────────────────────────────────────────────────────────────────────────── Testing for the string (length 36): 1234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ The characters in the string aren't all unique. The character 0 ('30'x) at position 10 is repeated at position 25
zkl
<lang zkl></lang> <lang zkl></lang>
- Output: