String matching: Difference between revisions

From Rosetta Code
Content added Content deleted
m (→‎{{header|Sidef}}: fixed the while loop)
(Added EchoLisp)
Line 821: Line 821:
println(string1.endsWith(string2))
println(string1.endsWith(string2))
}</lang>
}</lang>

=={{header|EchoLisp}}==
<lang lisp>
(string-suffix? "nette" "Antoinette") → #t
(string-prefix? "Simon" "Simon & Garfunkel") → #t

(string-match "Antoinette" "net") → #t ;; contains
(string-index "net" "Antoinette") → 5 ;; substring location
</lang>


=={{header|Elena}}==
=={{header|Elena}}==

Revision as of 19:58, 1 August 2015

Task
String matching
You are encouraged to solve this task according to the task description, using any language you may know.

Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.

You may see other such operations in the Basic Data Operations category, or:

Integer Operations
Arithmetic | Comparison

Boolean Operations
Bitwise | Logical

String Operations
Concatenation | Interpolation | Comparison | Matching

Memory Operations
Pointers & references | Addresses

Given two strings, demonstrate the following 3 types of matchings:

  1. Determining if the first string starts with second string
  2. Determining if the first string contains the second string at any location
  3. Determining if the first string ends with the second string

Optional requirements:

  1. Print the location of the match for part 2
  2. Handle multiple occurrences of a string for part 2.

Ada

<lang Ada> with Ada.Strings.Fixed; use Ada.Strings.Fixed; with Ada.Text_IO; use Ada.Text_IO;

procedure Match_Strings is 

  S1 : constant String := "abcd";
  S2 : constant String := "abab";
  S3 : constant String := "ab";

begin 

  if S1'Length >= S3'Length and then S1 (S1'First..S1'First + S3'Length - 1) = S3 then
     Put_Line ( & S1 & "' starts with '" & S3 & );
  end if;
  if S2'Length >= S3'Length and then S2 (S2'Last - S3'Length + 1..S2'Last) = S3 then
     Put_Line ( & S2 & "' ends with '" & S3 & );
  end if;
  Put_Line ( & S3 & "' first appears in '" & S1 & "' at" & Integer'Image (Index (S1, S3)));
  Put_Line
  (   & S3 & "' appears in '" & S2 &  &
     Integer'Image (Ada.Strings.Fixed.Count (S2, S3)) & " times"
  );

end Match_Strings; </lang>

Output:
'abcd' starts with 'ab'
'abab' ends with 'ab'
'ab' first appears in 'abcd' at 1
'ab' appears in 'abab' 2 times

Aime

<lang aime>text s, t; data b;

s = "Bangkok"; t = "Bang";

b_cast(b, s);

o_form("starts with, embeds, ends with \"~\": ~, ~, ~\n", t, b_seek(b, t) == 0, 

      b_seek(b, t) != -1,
      b_seek(b, t) != -1 && b_seek(b, t) + length(t) == length(s));

t = "ok";

o_form("starts with, embeds, ends with \"~\": ~, ~, ~\n", t, b_seek(b, t) == 0, 

      b_seek(b, t) != -1,
      b_seek(b, t) != -1 && b_seek(b, t) + length(t) == length(s));

t = "Summer";

o_form("starts with, embeds, ends with \"~\": ~, ~, ~\n", t, b_seek(b, t) == 0, 

      b_seek(b, t) != -1,
      b_seek(b, t) != -1 && b_seek(b, t) + length(t) == length(s));</lang>
Output:
starts with, embeds, ends with "Bang": 1, 1, 0
starts with, embeds, ends with "ok": 0, 1, 1
starts with, embeds, ends with "Summer": 0, 0, 0

ALGOL 68

Translation of: python
Works with: ALGOL 68 version Revision 1 - no extensions to language used
Works with: ALGOL 68G version Any - tested with release 1.18.0-9h.tiny

<lang algol68># define some appropriate OPerators # PRIO STARTSWITH = 5, ENDSWITH = 5; OP STARTSWITH = (STRING str, prefix)BOOL: # assuming LWB = 1 # 

 IF UPB str < UPB prefix THEN FALSE ELSE str[:UPB prefix]=prefix FI;

OP ENDSWITH = (STRING str, suffix)BOOL: # assuming LWB = 1 # 

 IF UPB str < UPB suffix THEN FALSE ELSE str[UPB str-UPB suffix+1:]=suffix FI;

INT loc, loc2;

print(( 

 "abcd" STARTSWITH "ab", # returns TRUE #
 "abcd" ENDSWITH "zn", # returns FALSE #
 string in string("bb",loc,"abab"), # returns FALSE #
 string in string("ab",loc,"abab"), # returns TRUE #
 (string in string("bb",loc,"abab")|loc|-1), # returns -1 #
 (string in string("ab",loc,"abab")|loc|-1), # returns +1 #
 (string in string("ab",loc2,"abab"[loc+1:])|loc+loc2|-1) # returns +3 #

))</lang>

Output:
TFFT         -1         +1         +3

AutoHotkey

<lang AutoHotkey> String1 = abcd String2 = abab

If (SubStr(String1,1,StrLen(String2)) = String2) 

MsgBox, "%String1%" starts with "%String2%".

IfInString, String1, %String2% { 

Position := InStr(String1,String2)
StringReplace, String1, String1, %String2%, %String2%, UseErrorLevel
MsgBox, "%String1%" contains "%String2%" at position %Position%`, and appears %ErrorLevel% times.

} StringRight, TempVar, String1, StrLen(String2) If TempVar = %String2% 

MsgBox, "%String1%" ends with "%String2%".

</lang>

AutoIt

<lang AutoIt>$string1 = "arduinoardblobard" $string2 = "ard"

== Determining if the first string starts with second string

If StringLeft($string1, StringLen($string2)) = $string2 Then ConsoleWrite("1st string starts with 2nd string." & @CRLF) Else ConsoleWrite("1st string does'nt starts with 2nd string." & @CRLF) EndIf

== Determining if the first string contains the second string at any location
== Print the location of the match for part 2
== Handle multiple occurrences of a string for part 2

$start = 1 $count = 0 $pos = StringInStr($string1, $string2) While $pos $count += 1 ConsoleWrite("1st string contains 2nd string at position: " & $pos & @CRLF) $pos = StringInStr($string1, $string2, 0, 1, $start + $pos + StringLen($string2)) WEnd If $count = 0 Then ConsoleWrite("1st string does'nt contain 2nd string." & @CRLF)

== Determining if the first string ends with the second string

If StringRight($string1, StringLen($string2)) = $string2 Then ConsoleWrite("1st string ends with 2nd string." & @CRLF) Else ConsoleWrite("1st string does'nt ends with 2nd string." & @CRLF) EndIf

</lang>

AWK

<lang AWK>#!/usr/bin/awk -f { 

   if ($1 ~ "^"$2) {

print $1" begins with "$2; 

   } else {

print $1" does not begin with "$2; 

   }

   if ($1 ~ $2) {

print $1" contains "$2; 

   } else {

print $1" does not contain "$2; 

   }

   if ($1 ~ $2"$") {

print $1" ends with "$2; 

   } else {

print $1" does not end with "$2; 

   }

} </lang>


BASIC

Works with: QBasic

<lang qbasic>first$ = "qwertyuiop"

'Determining if the first string starts with second string second$ = "qwerty" IF LEFT$(first$, LEN(second$)) = second$ THEN 

   PRINT "'"; first$; "' starts with '"; second$; "'"

ELSE 

   PRINT "'"; first$; "' does not start with '"; second$; "'"

END IF

'Determining if the first string contains the second string at any location 'Print the location of the match for part 2 second$ = "wert" x = INSTR(first$, second$) IF x THEN 

   PRINT "'"; first$; "' contains '"; second$; "' at position "; x

ELSE 

   PRINT "'"; first$; "' does not contain '"; second$; "'"

END IF

' Determining if the first string ends with the second string second$ = "random garbage" IF RIGHT$(first$, LEN(second$)) = second$ THEN 

   PRINT "'"; first$; "' ends with '"; second$; "'"

ELSE 

   PRINT "'"; first$; "' does not end with '"; second$; "'"

END IF

</lang>

Output:
'qwertyuiop' starts with 'qwerty'
'qwertyuiop' contains 'wert' at position  2
'qwertyuiop' does not end with 'random garbage'

Applesoft BASIC

<lang ApplesoftBasic>10 A$ = "THIS, THAT, AND THE OTHER THING" 20 S$ = "TH" 30 DEF FN S(P) = MID$(A$, P, LEN(S$)) = S$ 40 PRINT A$ : PRINT

110 S$(1) = "STARTS" 120 S$(0) = "DOES NOT START" 130 PRINT S$(FN S(1))" WITH "S$ : PRINT

210 R$ = "" : FOR I = 1 TO LEN(A$) - LEN(S$) : IF FN S(I) THEN R$ = R$ + STR$(I) + " " 220 NEXT I 230 IF LEN(R$) = 0 THEN PRINT "DOES NOT CONTAIN "S$ 240 IF LEN(R$) THEN PRINT "CONTAINS "S$" LOCATED AT POSITION "R$ 250 PRINT

310 E$(1) = "ENDS" 320 E$(0) = "DOES NOT END" 330 PRINT E$(FN S(LEN(A$) - LEN(S$) + 1))" WITH "S$</lang>

Batch File

<lang dos>::NOTE #1: This implementation might crash, or might not work properly if

you put some of the CMD special characters (ex. %,!, etc) inside the strings.
NOTE #2: The comparisons here are case-SENSITIVE.
NOTE #3: Spaces in strings are considered.

@echo off setlocal enabledelayedexpansion

The main things...

set "str1=qwertyuiop" set "str2=qwerty" call :str2_lngth call :matchbegin

set "str1=qweiuoiocghiioyiocxiisfguiioiuygvd" set "str2=io" call :str2_lngth call :matchcontain

set "str1=blablabla" set "str2=bbla" call :str2_lngth call :matchend

echo. pause exit /b 0

/The main things.
The functions...
matchbegin

echo. if "!str1:~0,%length%!"=="!str2!" ( echo "%str1%" begins with "%str2%". ) else ( echo "%str1%" does not begin with "%str2%". ) goto :EOF

matchcontain

echo. set curr=0&set exist=0

scanchrloop

if "!str1:~%curr%,%length%!"=="" ( if !exist!==0 echo "%str1%" does not contain "%str2%". goto :EOF ) if "!str1:~%curr%,%length%!"=="!str2!" ( echo "%str1%" contains "%str2%". ^(in Position %curr%^) set exist=1 ) set /a curr+=1&goto scanchrloop

matchend

echo. if "!str1:~-%length%!"=="!str2!" ( echo "%str1%" ends with "%str2%". ) else ( echo "%str1%" does not end with "%str2%". ) goto :EOF

str2_lngth

set length=0

loop

if "!str2:~%length%,1!"=="" goto :EOF set /a length+=1 goto loop

/The functions.</lang>
Output:
"qwertyuiop" begins with "qwerty".

"qweiuoiocghiioyiocxiisfguiioiuygvd" contains "io". (in Position 6)
"qweiuoiocghiioyiocxiisfguiioiuygvd" contains "io". (in Position 12)
"qweiuoiocghiioyiocxiisfguiioiuygvd" contains "io". (in Position 15)
"qweiuoiocghiioyiocxiisfguiioiuygvd" contains "io". (in Position 26)

"blablabla" does not end with "bbla".

Press any key to continue . . .


BBC BASIC

<lang bbcbasic> first$ = "The fox jumps over the dog" 

     FOR test% = 1 TO 3
       READ second$
       starts% = FN_first_starts_with_second(first$, second$)
       IF starts% PRINT """" first$ """ starts with """ second$ """"
       ends% = FN_first_ends_with_second(first$, second$)
       IF ends% PRINT """" first$ """ ends with """ second$ """"
       where% = FN_first_contains_second_where(first$, second$)
       IF where% PRINT """" first$ """ contains """ second$ """ at position " ; where%
       howmany% = FN_first_contains_second_howmany(first$, second$)
       IF howmany% PRINT """" first$ """ contains """ second$ """ " ; howmany% " time(s)"
     NEXT
     DATA "The", "he", "dog"
     END
     
     DEF FN_first_starts_with_second(A$, B$)
     = B$ = LEFT$(A$, LEN(B$))
     
     DEF FN_first_ends_with_second(A$, B$)
     = B$ = RIGHT$(A$, LEN(B$))
     
     DEF FN_first_contains_second_where(A$, B$)
     = INSTR(A$, B$)
     
     DEF FN_first_contains_second_howmany(A$, B$)
     LOCAL I%, N% : I% = 0
     REPEAT
       I% = INSTR(A$, B$, I%+1)
       IF I% THEN N% += 1
     UNTIL I% = 0
     = N%

</lang>

Output:
"The fox jumps over the dog" starts with "The"
"The fox jumps over the dog" contains "The" at position 1
"The fox jumps over the dog" contains "The" 1 time(s)
"The fox jumps over the dog" contains "he" at position 2
"The fox jumps over the dog" contains "he" 2 time(s)
"The fox jumps over the dog" ends with "dog"
"The fox jumps over the dog" contains "dog" at position 24
"The fox jumps over the dog" contains "dog" 1 time(s)

Bracmat

Bracmat does pattern matching in expressions subject:pattern and in strings @(subject:pattern). The (sub)pattern ? is a wild card. <lang Bracmat>( (sentence="I want a number such that that number will be even.") & out$(@(!sentence:I ?) & "sentence starts with 'I'" | "sentence does not start with 'I'") & out$(@(!sentence:? such ?) & "sentence contains 'such'" | "sentence does not contain 'such'") & out$(@(!sentence:? "even.") & "sentence ends with 'even.'" | "sentence does not end with 'even.'") & 0:?N & ( @(!sentence:? be (? & !N+1:?N & ~)) 

 | out$str$("sentence contains " !N " occurrences of 'be'")
 )

)</lang> In the last line, Bracmat is forced by the always failing node ~ to backtrack until all occurrences of 'be' are found. Thereafter the pattern match expression fails. The interesting part is the side effect: while backtracking, the accumulator N keeps track of how many are found.

Output:
sentence starts with 'I'
sentence contains 'such'
sentence ends with 'even.'
sentence contains 3 occurrences of 'be'

C

Case sensitive matching: <lang C>#include <string.h>

  1. include <stdio.h>

int startsWith(const char* container, const char* target) { 

 size_t clen = strlen(container), tlen = strlen(target);
 if (clen < tlen)
   return 0;
 return strncmp(container, target, tlen) == 0;

}

int endsWith(const char* container, const char* target) { 

 size_t clen = strlen(container), tlen = strlen(target);
 if (clen < tlen)
   return 0;
 return strncmp(container + clen - tlen, target, tlen) == 0;

}

int doesContain(const char* container, const char* target) { 

 return strstr(container, target) != 0;

}

int main(void) { 

 printf("Starts with Test ( Hello,Hell ) : %d\n", startsWith("Hello","Hell"));
 printf("Ends with Test ( Code,ode ) : %d\n", endsWith("Code","ode"));
 printf("Contains Test ( Google,msn ) : %d\n", doesContain("Google","msn"));

 return 0;

}</lang>

Output:
Starts with Test ( Hello,Hell ) : 1
Ends with Test ( Code,ode ) : 1
Contains Test ( Google,msn ) : 0

Code without using string library to demonstrate how char strings are just pointers: <lang C>#include <stdio.h>

/* returns 0 if no match, 1 if matched, -1 if matched and at end */ int s_cmp(const char *a, const char *b) { 

       char c1 = 0, c2 = 0;
       while (c1 == c2) {
               c1 = *(a++);
               if ('\0' == (c2 = *(b++)))
                       return c1 == '\0' ? -1 : 1;
       }
       return 0;

}

/* returns times matched */ int s_match(const char *a, const char *b) { 

       int i = 0, count = 0;
       printf("matching `%s' with `%s':\n", a, b);

       while (a[i] != '\0') {
               switch (s_cmp(a + i, b)) {
               case -1:
                       printf("matched: pos %d (at end)\n\n", i);
                       return ++count;
               case 1:
                       printf("matched: pos %d\n", i);
                       ++count;
                       break;
               }
               i++;
       }
       printf("end match\n\n");
       return count;

}

int main() { 

       s_match("A Short String", "ort S");
       s_match("aBaBaBaBa", "aBa");
       s_match("something random", "Rand");

       return 0;

}</lang>

Output:
matching `A Short String' with `ort S':
matched: pos 4
end match

matching `aBaBaBaBa' with `aBa':
matched: pos 0
matched: pos 2
matched: pos 4
matched: pos 6 (at end)

matching `something random' with `Rand':
end match

C++

<lang cpp>#include <string> using namespace std;

string s1="abcd"; string s2="abab"; string s3="ab"; //Beginning s1.compare(0,s3.size(),s3)==0; //End s1.compare(s1.size()-s3.size(),s3.size(),s3)==0; //Anywhere s1.find(s2)//returns string::npos int loc=s2.find(s3)//returns 0 loc=s2.find(s3,loc+1)//returns 2</lang>

C#

Works with: Mono version 2.6

<lang csharp> class Program { public static void Main (string[] args) { var value = "abcd".StartsWith("ab"); value = "abcd".EndsWith("zn"); //returns false value = "abab".Contains("bb"); //returns false value = "abab".Contains("ab"); //returns true int loc = "abab".IndexOf("bb"); //returns -1 loc = "abab".IndexOf("ab"); //returns 0 loc = "abab".IndexOf("ab",loc+1); //returns 2 } } </lang>

Clojure

Translation of: Java

<lang clojure>(def evals '((. "abcd" startsWith "ab") (. "abcd" endsWith "zn") (. "abab" contains "bb") (. "abab" contains "ab") (. "abab" indexOf "bb") (let [loc (. "abab" indexOf "ab")] (. "abab" indexOf "ab" (dec loc)))))

user> (for [i evals] [i (eval i)]) ([(. "abcd" startsWith "ab") true] [(. "abcd" endsWith "zn") false] [(. "abab" contains "bb") false] [(. "abab" contains "ab") true] [(. "abab" indexOf "bb") -1] [(let [loc (. "abab" indexOf "ab")] (. "abab" indexOf "ab" (dec loc))) 0])</lang>

CoffeeScript

This example uses string slices, but a better implementation might use indexOf for slightly better performance.

<lang coffeescript> matchAt = (s, frag, i) -> 

 s[i...i+frag.length] == frag

startsWith = (s, frag) -> 

 matchAt s, frag, 0

endsWith = (s, frag) -> 

 matchAt s, frag, s.length - frag.length

matchLocations = (s, frag) -> 

 (i for i in [0..s.length - frag.length] when matchAt s, frag, i)

console.log startsWith "tacoloco", "taco" # true console.log startsWith "taco", "tacoloco" # false console.log startsWith "tacoloco", "talk" # false console.log endsWith "tacoloco", "loco" # true console.log endsWith "loco", "tacoloco" # false console.log endsWith "tacoloco", "yoco" # false console.log matchLocations "bababab", "bab" # [0,2,4] console.log matchLocations "xxx", "x" # [0,1,2] </lang>

Common Lisp

<lang lisp> (defun starts-with-p (str1 str2) 

 "Determine whether `str1` starts with `str2`"
 (let ((p (search str2 str1)))
   (and p (= 0 p))))

(print (starts-with-p "foobar" "foo")) ; T (print (starts-with-p "foobar" "bar")) ; NIL

(defun ends-with-p (str1 str2) 

 "Determine whether `str1` ends with `str2`"
 (let ((p (mismatch str2 str1 :from-end T)))
   (or (not p) (= 0 p))))

(print (ends-with-p "foobar" "foo")) ; NIL (print (ends-with-p "foobar" "bar")) ; T

(defun containsp (str1 str2) 

 "Determine whether `str1` contains `str2`.
  Instead of just returning T, return a list of starting locations
  for every occurence of `str2` in `str1`"
  (unless (string-equal str2 "")
    (loop for p = (search str2 str1) then (search str2 str1 :start2 (1+ p))
          while p 
          collect p)))

(print (containsp "foobar" "oba")) ; (2) (print (containsp "ababaBa" "ba")) ; (1 3) (print (containsp "foobar" "x"))  ; NIL </lang>

Component Pascal

BlackBox Component Builder <lang oberon2> MODULE StringMatch; IMPORT StdLog,Strings; CONST strSize = 1024; patSize = 256;

TYPE Matcher* = POINTER TO LIMITED RECORD str: ARRAY strSize OF CHAR; pat: ARRAY patSize OF CHAR; pos: INTEGER END;

PROCEDURE NewMatcher*(IN str: ARRAY OF CHAR): Matcher; VAR m: Matcher; BEGIN NEW(m);m.str := str$;m.pos:= 0; RETURN m END NewMatcher;

PROCEDURE (m: Matcher) Match*(IN pat: ARRAY OF CHAR): INTEGER,NEW; VAR pos: INTEGER; BEGIN m.pat := pat$; pos := m.pos; Strings.Find(m.str,m.pat,pos,m.pos); RETURN m.pos END Match;

PROCEDURE (m: Matcher) Next*(): INTEGER, NEW; VAR pos: INTEGER; BEGIN pos := m.pos + LEN(m.pat$); Strings.Find(m.str,m.pat,pos,m.pos); RETURN m.pos; END Next;

(* Some Helper functions based on Strings module *) PROCEDURE StartsWith(IN str: ARRAY OF CHAR;IN pat: ARRAY OF CHAR): BOOLEAN; VAR pos: INTEGER; BEGIN Strings.Find(str,pat,0,pos); RETURN pos = 0 END StartsWith;

PROCEDURE Contains(IN str: ARRAY OF CHAR;IN pat: ARRAY OF CHAR; OUT pos: INTEGER): BOOLEAN; BEGIN Strings.Find(str,pat,0,pos); RETURN pos >= 0 END Contains;

PROCEDURE EndsWith(IN str: ARRAY OF CHAR;IN pat: ARRAY OF CHAR): BOOLEAN; VAR pos: INTEGER; BEGIN Strings.Find(str,pat,0,pos); RETURN pos + LEN(pat$) = LEN(str$) END EndsWith;

PROCEDURE Do*; CONST aStr = "abcdefghijklmnopqrstuvwxyz"; VAR pat: ARRAY 128 OF CHAR; res: BOOLEAN; at: INTEGER; m: Matcher; BEGIN (* StartsWith *) pat := "abc"; StdLog.String(aStr + " startsWith " + pat + " :>");StdLog.Bool(StartsWith(aStr,pat));StdLog.Ln; pat := "cba"; StdLog.String(aStr + " startsWith " + pat + " :>");StdLog.Bool(StartsWith(aStr,pat));StdLog.Ln; pat := "def"; StdLog.String(aStr + " startsWith " + pat + " :>");StdLog.Bool(StartsWith(aStr,pat));StdLog.Ln; StdLog.Ln; (* Contains *) pat := 'def'; StdLog.String(aStr + " contains " + pat + " :>");StdLog.Bool(Contains(aStr,pat,at)); StdLog.String(" at: ");StdLog.Int(at);StdLog.Ln; pat := 'efd'; StdLog.String(aStr + " contains " + pat + " :>");StdLog.Bool(Contains(aStr,pat,at)); StdLog.String(" at: ");StdLog.Int(at);StdLog.Ln; pat := 'abc'; StdLog.String(aStr + " contains " + pat + " :>");StdLog.Bool(Contains(aStr,pat,at)); StdLog.String(" at: ");StdLog.Int(at);StdLog.Ln; pat := 'xyz'; StdLog.String(aStr + " contains " + pat + " :>");StdLog.Bool(Contains(aStr,pat,at)); StdLog.String(" at: ");StdLog.Int(at);StdLog.Ln; StdLog.Ln; (* EndsWith *) pat := 'xyz'; StdLog.String(aStr + " endsWith " + pat + " :>");StdLog.Bool(EndsWith(aStr,pat));StdLog.Ln; pat := 'zyx'; StdLog.String(aStr + " endsWith " + pat + " :>");StdLog.Bool(EndsWith(aStr,pat));StdLog.Ln; pat := 'abc'; StdLog.String(aStr + " endsWith " + pat + " :>");StdLog.Bool(EndsWith(aStr,pat));StdLog.Ln; pat:= 'def'; StdLog.String(aStr + " endsWith " + pat + " :>");StdLog.Bool(EndsWith(aStr,pat));StdLog.Ln; StdLog.Ln;

m := NewMatcher("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz"); StdLog.String("Matching 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz' against 'abc':> "); StdLog.Ln; StdLog.String("Match at: ");StdLog.Int(m.Match("abc"));StdLog.Ln; StdLog.String("Match at: ");StdLog.Int(m.Next());StdLog.Ln; StdLog.String("Match at: ");StdLog.Int(m.Next());StdLog.Ln END Do; END StringMatch. </lang> Execute: ^Q StringMatching.Do

Output:
abcdefghijklmnopqrstuvwxyz startsWith abc :> $TRUE
abcdefghijklmnopqrstuvwxyz startsWith cba :> $FALSE
abcdefghijklmnopqrstuvwxyz startsWith def :> $FALSE

abcdefghijklmnopqrstuvwxyz contains def :> $TRUE at:  3
abcdefghijklmnopqrstuvwxyz contains efd :> $FALSE at:  -1
abcdefghijklmnopqrstuvwxyz contains abc :> $TRUE at:  0
abcdefghijklmnopqrstuvwxyz contains xyz :> $TRUE at:  23

abcdefghijklmnopqrstuvwxyz endsWith xyz :> $TRUE
abcdefghijklmnopqrstuvwxyz endsWith zyx :> $FALSE
abcdefghijklmnopqrstuvwxyz endsWith abc :> $FALSE
abcdefghijklmnopqrstuvwxyz endsWith def :> $FALSE

Matching 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz' against 'abc':> 
Match at:  0
Match at:  26
Match at:  -1

D

<lang d>void main() { 

   import std.stdio;
   import std.algorithm: startsWith, endsWith, find, countUntil;

   "abcd".startsWith("ab").writeln;      // true
   "abcd".endsWith("zn").writeln;        // false
   "abab".find("bb").writeln;            // empty array (no match)
   "abcd".find("bc").writeln;            // "bcd" (substring start
                                          //        at match)
   "abab".countUntil("bb").writeln;      // -1 (no match)
   "abab".countUntil("ba").writeln;      //  1 (index of 1st match)

   // std.algorithm.startsWith also works on arrays and ranges:
   [1, 2, 3].countUntil(3).writeln;      //  2
   [1, 2, 3].countUntil([2, 3]).writeln; //  1

}</lang>

Output:
true
false

bcd
-1
1
2
1

DCL

<lang DCL>$ first_string = p1 $ length_of_first_string = f$length( first_string ) $ second_string = p2 $ length_of_second_string = f$length( second_string ) $ offset = f$locate( second_string, first_string ) $ if offset .eq. 0 $ then $ write sys$output "first string starts with second string" $ else $ write sys$output "first string does not start with second string" $ endif $ if offset .ne. length_of_first_string $ then $ write sys$output "first string contains the second string at location ", offset $ else $ write sys$output "first string does not contain the second string at any location" $ endif $ temp = f$extract( length_of_first_string - length_of_second_string, length_of_second_string, first_string ) $ if second_string .eqs. temp $ then $ write sys$output "first string ends with the second string" $ else $ write sys$output "first string does not end with the second string" $ endif</lang>

Output:
$ @string_matching efabcdef ef
first string starts with second string
first string contains the second string at location 0
first string ends with the second string
$ @string_matching efabcdef ab
first string does not start with second string
first string contains the second string at location 2
first string does not end with the second string
$ @string_matching efabcdef def
first string does not start with second string
first string contains the second string at location 5
first string ends with the second string
$ @string_matching efabcdef defx
first string does not start with second string
first string does not contain the second string at any location
first string does not end with the second string

Delphi

<lang Delphi>program CharacterMatching;

{$APPTYPE CONSOLE}

uses StrUtils;

begin 

 WriteLn(AnsiStartsText('ab', 'abcd')); // True
 WriteLn(AnsiEndsText('zn', 'abcd')); // False
 WriteLn(AnsiContainsText('abcd', 'bb')); // False
 Writeln(AnsiContainsText('abcd', 'ab')); // True
 WriteLn(Pos('ab', 'abcd')); // 1

end.</lang>

E

<lang e>def f(string1, string2) { 

   println(string1.startsWith(string2))
   
   var index := 0
   while ((index := string1.startOf(string2, index)) != -1) {
       println(`at $index`)
       index += 1
   }

   println(string1.endsWith(string2))

}</lang>

EchoLisp

<lang lisp> (string-suffix? "nette" "Antoinette") → #t (string-prefix? "Simon" "Simon & Garfunkel") → #t

(string-match "Antoinette" "net") → #t ;; contains (string-index "net" "Antoinette") → 5  ;; substring location </lang>

Elena

<lang elena>#define system.

  1. define system'routines.
  2. define extensions.
  1. symbol program =

[ 

   #var s :="hello".
   
   (s startingWith:"hel") ?
   [
       console writeLine:s:" starts with hel".
   ].
   
   (s endingWith:"llo") ?
   [
       console writeLine:s:" ends with llo".
   ].

   (s containing:"hello") ?
   [
       console writeLine:s:" contains el".
   ].

].</lang>

Elixir

The String module has functions that cover the base requirements. <lang elixir> s1 = "abcd" s2 = "adab" s3 = "ab"

String.starts_with?(s1, s3)

  1. => true

String.starts_with?(s2, s3)

  1. => false

String.ends_with?(s1, s3)

  1. => false

String.ends_with?(s2, s3)

  1. => true

String.contains?(s1, s3)

  1. => true

String.contains?(s2, s3)

  1. => true

</lang>

Erlang

<lang erlang> -module(character_matching). -export([starts_with/2,ends_with/2,contains/2]).

%% Both starts_with and ends_with are mappings to 'lists:prefix/2' and %% 'lists:suffix/2', respectively.

starts_with(S1,S2) -> 

   lists:prefix(S2,S1).

ends_with(S1,S2) -> 

   lists:suffix(S2,S1).

contains(S1,S2) -> 

   contains(S1,S2,1,[]).

%% While S1 is at least as long as S2 we check if S2 is its prefix, %% storing the result if it is. When S1 is shorter than S2, we return %% the result. NB: this will work on any arbitrary list in erlang %% since it makes no distinction between strings and lists. contains([_|T]=S1,S2,N,Acc) when length(S2) =< length(S1) -> 

   case starts_with(S1,S2) of
       true ->
           contains(T,S2,N+1,[N|Acc]);
       false ->
           contains(T,S2,N+1,Acc)
   end;

contains(_S1,_S2,_N,Acc) -> 

   Acc.

</lang>

Euphoria

<lang euphoria>sequence first, second integer x

first = "qwertyuiop"

-- Determining if the first string starts with second string second = "qwerty" if match(second, first) = 1 then 

   printf(1, "'%s' starts with '%s'\n", {first, second})

else 

   printf(1, "'%s' does not start with '%s'\n", {first, second})

end if

-- Determining if the first string contains the second string at any location -- Print the location of the match for part 2 second = "wert" x = match(second, first) if x then 

   printf(1, "'%s' contains '%s' at position %d\n", {first, second, x})

else 

   printf(1, "'%s' does not contain '%s'\n", {first, second})

end if

-- Determining if the first string ends with the second string second = "uio" if length(second)<=length(first) and match_from(second, first, length(first)-length(second)+1) then 

   printf(1, "'%s' ends with '%s'\n", {first, second})

else 

   printf(1, "'%s' does not end with '%s'\n", {first, second})

end if</lang>

Output:
'qwertyuiop' starts with 'qwerty'
'qwertyuiop' contains 'wert' at position 2
'qwertyuiop' does not end with 'uio'

F#

<lang fsharp>[<EntryPoint>] let main args = 

   let text = "一二三四五六七八九十"
   let starts = "一二"
   let ends = "九十"
   let contains = "五六"
   let notContains = "百"

   printfn "text = %A" text
   printfn "starts with %A: %A" starts (text.StartsWith(starts))
   printfn "starts with %A: %A" ends (text.StartsWith(ends))
   printfn "ends with %A: %A" ends (text.EndsWith(ends))
   printfn "ends with %A: %A" starts (text.EndsWith(starts))
   printfn "contains %A: %A" contains (text.Contains(contains))
   printfn "contains %A: %A" notContains (text.Contains(notContains))
   printfn "substring %A begins at position %d (zero-based)" contains (text.IndexOf(contains))
   let text2 = text + text
   printfn "text = %A" text2
   Seq.unfold (fun (n : int) ->
           let idx = text2.IndexOf(contains, n)
           if idx < 0 then None else Some (idx, idx+1)) 0
   |> Seq.iter (printfn "substring %A begins at position %d (zero-based)" contains)
   0</lang>
Output:
text = "一二三四五六七八九十"
starts with "一二": true
starts with "九十": false
ends with "九十": true
ends with "一二": false
contains "五六": true
contains "百": false
substring "五六" begins at position 4 (zero-based)
text = "一二三四五六七八九十一二三四五六七八九十"
substring "五六" begins at position 4 (zero-based)
substring "五六" begins at position 14 (zero-based)

Fantom

Fantom provides several self-explanatory string-matching methods:

  • startsWith
  • endsWith
  • contains
  • index (takes an optional index, for the start position)
  • indexIgnoreCase (like above, ignoring case for ASCII characters)
  • indexr (start search from end of string, with an optional index)
  • indexrIgnoreCase (like above, ignoring case for ASCII characters)

<lang fantom> class Main { 

 public static Void main ()
 {
   string := "Fantom Language"
   echo ("String is: " + string)
   echo ("does string start with 'Fantom'? " + string.startsWith("Fantom"))
   echo ("does string start with 'Language'? " + string.startsWith("Language"))
   echo ("does string contain 'age'? " + string.contains("age"))
   echo ("does string contain 'page'? " + string.contains("page"))
   echo ("does string end with 'Fantom'? " + string.endsWith("Fantom"))
   echo ("does string end with 'Language'? " + string.endsWith("Language"))

   echo ("Location of 'age' is: " + string.index("age"))
   posn := string.index ("an")
   echo ("First location of 'an' is: " + posn)
   posn = string.index ("an", posn+1)
   echo ("Second location of 'an' is: " + posn)
   posn = string.index ("an", posn+1)
   if (posn == null) echo ("No third location of 'an'")
 }

} </lang>

Output:
String is: Fantom Language
does string start with 'Fantom'? true
does string start with 'Language'? false
does string contain 'age'? true
does string contain 'page'? false
does string end with 'Fantom'? false
does string end with 'Language'? true
Location of 'age' is: 12
First location of 'an' is: 1
Second location of 'an' is: 8
No third location of 'an'

FBSL

<lang qbasic>#APPTYPE CONSOLE

DIM s = "roko, mat jane do"

IF LEFT(s, 4) = "roko" THEN PRINT STRENC(s), " starts with ", STRENC("roko") IF INSTR(s, "mat") THEN PRINT STRENC(s), " contains ", STRENC("mat"), " at ", INSTR IF RIGHT(s, 2) = "do" THEN PRINT STRENC(s), " ends with ", STRENC("do") PRINT STRENC(s), " contains ", STRENC("o"), " at the following locations:", InstrEx(s, "o")

PAUSE

SUB InstrEx(mane, match) 

   INSTR = 0
   WHILE INSTR(mane, match, INSTR + 1): PRINT " ", INSTR;: WEND

END SUB </lang>

Output:
"roko, mat jane do" starts with "roko"
"roko, mat jane do" contains "mat" at 7
"roko, mat jane do" ends with "do"
"roko, mat jane do" contains "o" at the following locations: 2 4 17

Press any key to continue...

Forth

<lang forth>: starts-with ( a l a2 l2 -- ? ) 

 tuck 2>r min 2r> compare 0= ;
ends-with ( a l a2 l2 -- ? )
 tuck 2>r negate over + 0 max /string 2r> compare 0= ;

\ use SEARCH ( a l a2 l2 -- a3 l3 ? ) for contains</lang>

GML

Translation of: BASIC

<lang GML>#define charMatch { 

   first = "qwertyuiop";

   // Determining if the first string starts with second string 
   second = "qwerty";
   if (string_pos(second, first) > 0) {
       show_message("'" + first + "' starts with '" + second + "'");
   } else {
       show_message("'" + first + "' does not start with '" + second + "'");
   }

   second = "wert"
   // Determining if the first string contains the second string at any location
   // Print the location of the match for part 2
   if (string_pos(second, first) > 0) {
       show_message("'" + first + "' contains '" + second + "' at position " + string(x));
   } else {
       show_message("'" + first + "' does not contain '" + second + "'");
   }
   // Handle multiple occurrences of a string for part 2.
   x = string_count(second, first);
   show_message("'" + first + "' contains " + string(x) + " instances of '" + second + "'");

// Determining if the first string ends with the second string 

   second = "random garbage"
   temp = string_copy(first,
                      (string_length(first) - string_length(second)) + 1, 
                      string_length(second));
   if (temp == second) {
       show_message("'" + first + "' ends with '" + second + "'");
   } else {
       show_message("'" + first + "' does not end with '" + second + "'");
   }

}</lang>

Output:

(in message boxes, 1 per line) 

'qwertyuiop' starts with 'qwerty'
'qwertyuiop' contains 'wert' at position 0
'qwertyuiop' contains 1 instances of 'wert'
'qwertyuiop' does not end with 'random garbage'

Go

<lang go>package main

import ( 

   "fmt"
   "strings"

)

func match(first, second string) { 

   fmt.Printf("1. %s starts with %s: %t\n",
       first, second, strings.HasPrefix(first, second))
   i := strings.Index(first, second)
   fmt.Printf("2. %s contains %s: %t,\n", first, second, i >= 0)
   if i >= 0 {
       fmt.Printf("2.1. at location %d,\n", i)
       for start := i+1;; {
           if i = strings.Index(first[start:], second); i < 0 {
               break
           }
           fmt.Printf("2.2. at location %d,\n", start+i)
           start += i+1
       }
       fmt.Println("2.2. and that's all")
   }
   fmt.Printf("3. %s ends with %s: %t\n",
       first, second, strings.HasSuffix(first, second))

}

func main() { 

   match("abracadabra", "abr")

}</lang>

Output:
1. abracadabra starts with abr: true
2. abracadabra contains abr: true,
2.1. at location 0,
2.2. at location 7,
2.2. and that's all
3. abracadabra ends with abr: false

Groovy

Examples: <lang groovy>assert "abcd".startsWith("ab") assert ! "abcd".startsWith("zn") assert "abcd".endsWith("cd") assert ! "abcd".endsWith("zn") assert "abab".contains("ba") assert ! "abab".contains("bb")


assert "abab".indexOf("bb") == -1 // not found flag assert "abab".indexOf("ab") == 0

def indicesOf = { string, substring -> 

   if (!string) { return [] }
   def indices = [-1]
   while (true) {
       indices << string.indexOf(substring, indices.last()+1)
       if (indices.last() == -1) break
   }
   indices[1..<(indices.size()-1)]

} assert indicesOf("abab", "ab") == [0, 2] assert indicesOf("abab", "ba") == [1] assert indicesOf("abab", "xy") == []</lang>

All assertions pass, so there is no output.

Haskell

<lang haskell>> import Data.List > "abc" `isPrefixOf` "abcdefg" True > "efg" `isSuffixOf` "abcdefg" True > "bcd" `isInfixOf` "abcdefg" True > "abc" `isInfixOf` "abcdefg" -- Prefixes and suffixes are also infixes True > let infixes a b = findIndices (isPrefixOf a) $ tails b > infixes "ab" "abcdefabqqab" [0,6,10]</lang>

Icon and Unicon

<lang Icon>procedure main() 

  write("Matching s2 :=",image(s2 := "ab")," within s1:= ",image(s1 := "abcdabab"))

  write("Test #1 beginning ",if match(s2,s1) then "matches " else "failed")
  writes("Test #2 all matches at positions [") 
     every writes(" ",find(s2,s1)|"]\n")
  write("Test #3 ending ", if s1[0-:*s2] == s2 then "matches" else "fails")

end</lang>

Output:
Matching s2 :="ab" within s1:= "abcdabab"
Test #1 beginning matches
Test #2 all matches at positions [ 1 5 7 ]
Test #3 ending matches

J

<lang j>startswith=: ] -: ({.~ #) contains=: +./@:E.~ endswith=: ] -: ({.~ -@#)</lang>

Example use:

<lang j> 'abcd' startswith 'ab' 1 

  'abcd' startswith 'cd'

0 

  'abcd' endswith 'ab'

0 

  'abcd' endswith 'cd'

1 

  'abcd' contains 'bb'

0 

  'abcd' contains 'ab'

1 

  'abcd' contains 'bc'

1 

  'abab' contains 'ab'

1 

  'abab' I.@E.~ 'ab'       NB. find starting indicies

0 2</lang>

Note that these verbs contain no constraints restricting them to sequences of characters and so also apply to arrays of type other than character: <lang j> 0 1 2 3 startswith 0 1 NB. integer 1 

  4.2 5.1 1.3 9 3 contains 1.3 4.2     NB. floating point

0 

  4.2 5.1 1.3 4.2 9 3 contains 1.3 4.2

1</lang>

Java

<lang java>"abcd".startsWith("ab") //returns true "abcd".endsWith("zn") //returns false "abab".contains("bb") //returns false "abab".contains("ab") //returns true int loc = "abab".indexOf("bb") //returns -1 loc = "abab".indexOf("ab") //returns 0 loc = "abab".indexOf("ab",loc+1) //returns 2</lang>

JavaScript

<lang javascript>var stringA = "tacoloco" 

 , stringB = "co"
 , q1, q2, q2multi, m
 , q2matches = []

// stringA starts with stringB q1 = stringA.substring(0, stringB.length) == stringB

// stringA contains stringB q2 = stringA.indexOf(stringB)

// multiple matches q2multi = new RegExp(stringB,'g')

while(m = q2multi.exec(stringA)){ q2matches.push(m.index) }

// stringA ends with stringB q3 = stringA.substr(-stringB.length) == stringB

console.log("1: Does '"+stringA+"' start with '"+stringB+"'? " + ( q1 ? "Yes." : "No.")) console.log("2: Is '"+stringB+"' contained in '"+stringA+"'? " + (~q2 ? "Yes, at index "+q2+"." : "No.")) if (~q2 && q2matches.length > 1){ console.log(" In fact, it happens "+q2matches.length+" times within '"+stringA+"', at index"+(q2matches.length > 1 ? "es" : "")+" "+q2matches.join(', ')+".") } console.log("3: Does '"+stringA+"' end with '"+stringB+"'? " + ( q3 ? "Yes." : "No."))</lang>

Output:
1: Does 'tacoloco' start with 'co'? No.
2: Is 'co' contained in 'tacoloco'? Yes, at index 2.
   In fact, it happens 2 times within 'tacoloco', at indexes 2, 6.
3: Does 'tacoloco' end with 'co'? Yes.

Lasso

<lang Lasso>local( 

a = 'a quick brown peanut jumped over a quick brown fox',
b = 'a quick brown'

)

//Determining if the first string starts with second string

  1. a->beginswith(#b) // true

//Determining if the first string contains the second string at any location

  1. a >> #b // true
  2. a->contains(#b) // true

//Determining if the first string ends with the second string

  1. a->endswith(#b) // false</lang>

jq

Using the builtins of jq 1.4 and later: <lang jq># startswith/1 is boolean: "abc" | startswith("ab")

  1. => true</lang>

<lang jq># index/1 returns the index or null,

  1. so the jq test "if index(_) then ...." can be used
  2. without any type conversion.

"abcd" | index( "bc")

  1. => 1</lang>

<lang jq># endswith/1 is also boolean: "abc" | endswith("bc")

  1. => true</lang>

Using the regex functions available in jq 1.5: <lang jq>"abc" | test( "^ab")

"abcd" | test("bc")

"abcd" | test("cd$")</lang>

Multiple Occurrences

To determine all the indices of one string in another: <lang sh># In jq 1.4 or later: jq -n '"abcdabcd" | indices("bc")' [ 

 1,
 5

]</lang>

In jq 1.5, the regex function match/1 can also be used: <lang sh>$ jq -n '"abcdabcd" | match("bc"; "g") | .offset' 1 5</lang>


Julia

<lang julia>begins_with("abcd","ab") #returns true search("abcd","ab") #returns 1:2, indices range where string was found ends_with("abcd","zn") #returns false ismatch(r"ab","abcd") #returns true where 1st arg is regex string julia>for r in each_match(r"ab","abab") println(r.offset) end 1 3</lang>

K

<lang k>startswith: {:[0<#p:_ss[x;y];~*p;0]} endswith: {0=(-#y)+(#x)-*_ss[x;y]} contains: {0<#_ss[x;y]}</lang>

Example:

<lang k> startswith["abcd";"ab"] 1 

 startswith["abcd";"bc"]

0 

 endswith["abcd";"cd"]

1 

 endswith["abcd";"bc"]

0 

 contains["abcdef";"cde"]

1 

 contains["abcdef";"bdef"]

0 

 _ss["abcdabceabc";"abc"]    / location of matches

0 4 8</lang>

LabVIEW

These images solve the task's requirements in order.
This image is a VI Snippet, an executable image of LabVIEW code. The LabVIEW version is shown on the top-right hand corner. You can download it, then drag-and-drop it onto the LabVIEW block diagram from a file browser, and it will appear as runnable, editable code.


Lang5

<lang lang5>: 2array 2 compress ; : bi* '_ set dip _ execute ;  : bi@ dup bi* ;

comb "" split ;  : concat "" join ;  : dip swap '_ set execute _ ;
first 0 extract swap drop ; : flip comb reverse concat ;
contains
   swap 'comb bi@ length do                    # create a matrix.
        1 - "dup 1 1 compress rotate" dip dup 0 == if break then
   loop drop length compress swap drop
   "length 1 -" bi@ rot 0 0 "'2array dip" '2array bi* swap 2array slice reverse
   : concat.(*)  concat ;
   'concat "'concat. apply" bi* eq 1 1 compress index collapse
   length if expand drop else drop 0 then ;    # r: position.
end-with 'flip bi@ start-with ;
start-with 'comb bi@ length rot swap iota subscript 'concat bi@ eq ;

"rosettacode" "rosetta" start-with . # 1 "rosettacode" "taco" contains . # 5 "rosettacode" "ocat" contains . # 0 "rosettacode" "edoc" end-with . # 0 "rosettacode" "code" contains . # 7</lang>

Liberty BASIC

<lang lb>'1---Determining if the first string starts with second string st1$="first string" st2$="first" if left$(st1$,len(st2$))=st2$ then 

   print "First string starts with second string."

end if

'2---Determining if the first string contains the second string at any location '2.1---Print the location of the match for part 2 st1$="Mississippi" st2$="i" if instr(st1$,st2$) then 

   print "First string contains second string."
   print "Second string is at location ";instr(st1$,st2$)

end if

'2.2---Handle multiple occurrences of a string for part 2. pos=instr(st1$,st2$) while pos 

   count=count+1
   pos=instr(st1$,st2$,pos+len(st2$))

wend print "Number of times second string appears in first string is ";count

'3---Determining if the first string ends with the second string st1$="first string" st2$="string" if right$(st1$,len(st2$))=st2$ then 

   print "First string ends with second string."

end if 

</lang>

<lang logo>to starts.with? :sub :thing 

 if empty? :sub [output "true]
 if empty? :thing [output "false]
 if not equal? first :sub first :thing [output "false]
 output starts.with? butfirst :sub butfirst :thing

end

to ends.with? :sub :thing 

 if empty? :sub [output "true]
 if empty? :thing [output "false]
 if not equal? last :sub last :thing [output "false]
 output ends.with? butlast :sub butlast :thing

end

show starts.with? "dog "doghouse  ; true show ends.with? "house "doghouse  ; true show substring? "gho "doghouse  ; true (built-in)</lang>

Lua

<lang lua>s1 = "string" s2 = "str" s3 = "ing" s4 = "xyz"

print( "s1 starts with s2: ", string.find( s1, s2 ) == 1 ) print( "s1 starts with s3: ", string.find( s1, s3 ) == 1, "\n" )

print( "s1 contains s3: ", string.find( s1, s3 ) ~= nil ) print( "s1 contains s3: ", string.find( s1, s4 ) ~= nil, "\n" )

print( "s1 ends with s2: ", select( 2, string.find( s1, s2 ) ) == string.len( s1 ) ) print( "s1 ends with s3: ", select( 2, string.find( s1, s3 ) ) == string.len( s1 ) )</lang>

Maple

These facilities are all to be found in the StringTools package in Maple. <lang Maple> > with( StringTools ): # bind package exports at the top-level > s := "dzrIemaWWIMidXYZwGiqkOOn": > s[1..4]; # pick a prefix 

                                "dzrI"

> IsPrefix( s[ 1 .. 4 ], s ); # check it 

                                 true

> s[ -4 .. -1 ]; # pick a suffix 

                                "kOOn"

> IsSuffix( s[ -4 .. -1 ], s ); # check it 

                                 true

> p := Search( "XYZ", s ); # find a substring 

                               p := 14

> s[ p .. p + 2 ]; # check 

                                "XYZ"

> SearchAll( [ "WWI", "XYZ" ], s ); # search for multiple patterns 

                           [8, 1], [14, 2]

> to 3 do s := cat( s, s ) end: length( s ); # build a longer string by repeated doubling 

                                 192

> p := SearchAll( "XYZ", s ); # find all occurrences 

               p := 14, 38, 62, 86, 110, 134, 158, 182

> {seq}( s[ i .. i + 2 ], i = p ); # check them 

                               {"XYZ"}

</lang> The StringTools package also contains facilities for regular expression matching, but for fixed string patterns, the Search and SearchAll tools are much faster.

Mathematica

<lang Mathematica>StartWith[x_, y_] := MemberQ[Flatten[StringPosition[x, y]], 1] EndWith[x_, y_] := MemberQ[Flatten[StringPosition[x, y]], StringLength[x]] StartWith["XYZaaabXYZaaaaXYZXYZ", "XYZ"] EndWith["XYZaaabXYZaaaaXYZXYZ", "XYZ"] StringPosition["XYZaaabXYZaaaaXYZXYZ", "XYZ"]</lang>

Output:
True
True
{{1,3},{8,10},{15,17},{18,20}}


MATLAB / Octave

<lang Matlab> 

  % 1. Determining if the first string starts with second string

strcmp(str1,str2,length(str2)) 

  % 2. Determining if the first string contains the second string at any location

~isempty(strfind(s1,s2)) 

  % 3. Determining if the first string ends with the second string

( (length(str1)>=length(str2)) && strcmp(str1(end+[1-length(str2):0]),str2) ) 

  % 1. Print the location of the match for part 2

disp(strfind(s1,s2)) 

  % 2. Handle multiple occurrences of a string for part 2.

ix = strfind(s1,s2);  % ix is a vector containing the starting positions of s2 within s1 </lang>


NetRexx

<lang NetRexx>/* NetRexx */ options replace format comments java crossref savelog symbols

lipsum = x_ = 0 x_ = x_ + 1; lipsum[0] = x_; lipsum[x_] = 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.' x_ = x_ + 1; lipsum[0] = x_; lipsum[x_] = lipsum[1].reverse

srch = srch[1] = 'Lorem ipsum dolor sit amet' srch[2] = 'consectetur adipisicing elit' srch[3] = 'dolore magna aliqua.'

loop j_ = 1 to lipsum[0] 

 x1 = lipsum[j_].pos(srch[1])
 x2 = lipsum[j_].pos(srch[2])
 x3 = lipsum[j_].lastpos(srch[3])

 report(x1 = 1, lipsum[j_], srch[1], 'Test string starts with search string:', 'Test string does not start with search string:')
 report(x2 > 0, lipsum[j_], srch[2], 'Search string located in test string at position:' x2,  'Search string not found within test string:')
 report(x3 \= srch[3].length, lipsum[j_], srch[3], 'Test string ends with search string:', 'Test string does not start with search string:')
 end j_

many = x_ = 0 x_ = x_ + 1; many[0] = x_; many[x_] = 'How many times does "many times" occur in this string?' x_ = x_ + 1; many[0] = x_; many[x_] = 'How often does "many times" occur in this string?' x_ = x_ + 1; many[0] = x_; many[x_] = 'How often does it occur in this string?' srch[4] = 'many times'

loop j_ = 1 to many[0] 

 o_ = 0
 k_ = 0
 loop label dups until o_ = 0
   o_ = many[j_].pos(srch[4], o_ + 1)
   if o_ \= 0 then k_ = k_ + 1
   end dups
 report(k_ > 0, many[j_], srch[4], 'Number of times search string occurs:' k_, 'Search string not found')
 end j_

method report(state = boolean, ts, ss, testSuccess, testFailure) public static 

 if state then say testSuccess
 else          say testFailure
 say '    Test string:' ts
 say '  Search string:' ss
 say

 return

</lang>

NewLISP

<lang NewLISP>(setq str "abcdefbcghi")

test if str starts with "ab"

(starts-with str "ab")

find "bc" inside str

(find "bc" str)

test if str ends with "ghi"

(ends-with str "ghi")

find all positions of pattern inside str

(define (find-all-pos pattern str) 

 (let ((idx -1) (pos '()))
   (while (setq idx (find pattern str 0 (+ idx 1)))
     (push idx pos -1))))

(find-all-pos "bc" str)</lang>

Nim

<lang nim>import strutils

var s: string = "The quick brown fox" if startsWith(s, "The quick"): 

  echo("Starts with: The quick")

if endsWith(s, "brown Fox"): 

  echo("Ends with: brown fox")

var pos = find(s, " brown ") # -1 if not found if contains(s, " brown "): # showing the contains() proc, but could use if pos!=-1: 

  echo('"' & " brown " & '"' & " is located at position: " & $pos)</lang>
Output:
Starts with: The quick
Ends with: brown fox
" brown " is located at position: 9

Objective-C

<lang objc>[@"abcd" hasPrefix:@"ab"] //returns true [@"abcd" hasSuffix:@"zn"] //returns false int loc = [@"abab" rangeOfString:@"bb"].location //returns -1 loc = [@"abab" rangeOfString:@"ab"].location //returns 0 loc = [@"abab" rangeOfString:@"ab" options:0 range:NSMakeRange(loc+1, [@"abab" length]-(loc+1))].location //returns 2</lang>

Objeck

<lang objeck> bundle Default { 

 class Matching {
   function : Main(args : System.String[]) ~ Nil {
     "abcd"->StartsWith("ab")->PrintLine(); # returns true
     "abcd"->EndsWith("zn")->PrintLine(); # returns false
     ("abab"->Find("bb") <> -1)->PrintLine(); # returns false
     ("abab"->Find("ab") <> -1)->PrintLine(); # returns true
     loc := "abab"->Find("bb"); # returns -1
     loc := "abab"->Find("ab"); # returns 0
     loc := "abab"->Find("ab", loc + 1); # returns 2
   }
 }

} </lang>

OCaml

<lang ocaml>let match1 s1 s2 = 

 let len1 = String.length s1
 and len2 = String.length s2 in
 if len1 < len2 then false else
   let sub = String.sub s1 0 len2 in
   (sub = s2)</lang>

testing in the top-level: 

# match1 "Hello" "Hello World!" ;;
- : bool = false
# match1 "Hello World!" "Hello" ;;
- : bool = true

<lang ocaml>let match2 s1 s2 = 

 let len1 = String.length s1
 and len2 = String.length s2 in
 if len1 < len2 then false else
   let rec aux i =
     if i < 0 then false else
       let sub = String.sub s1 i len2 in
       if (sub = s2) then true else aux (pred i)
   in
   aux (len1 - len2)</lang>

# match2 "It's raining, Hello World!" "umbrella" ;;
- : bool = false
# match2 "It's raining, Hello World!" "Hello" ;;
- : bool = true

<lang ocaml>let match3 s1 s2 = 

 let len1 = String.length s1
 and len2 = String.length s2 in
 if len1 < len2 then false else
   let sub = String.sub s1 (len1 - len2) len2 in
   (sub = s2)</lang>

# match3 "Hello World" "Hello" ;;
- : bool = false
# match3 "Hello World" "World" ;;
- : bool = true

<lang ocaml>let match2_loc s1 s2 = 

 let len1 = String.length s1
 and len2 = String.length s2 in
 if len1 < len2 then (false, -1) else
   let rec aux i =
     if i < 0 then (false, -1) else
       let sub = String.sub s1 i len2 in
       if (sub = s2) then (true, i) else aux (pred i)
   in
   aux (len1 - len2)</lang>

# match2_loc "The sun's shining, Hello World!" "raining" ;;
- : bool * int = (false, -1)
# match2_loc "The sun's shining, Hello World!" "shining" ;;
- : bool * int = (true, 10)

<lang ocaml>let match2_num s1 s2 = 

 let len1 = String.length s1
 and len2 = String.length s2 in
 if len1 < len2 then (false, 0) else
   let rec aux i n =
     if i < 0 then (n <> 0, n) else
       let sub = String.sub s1 i len2 in
       if (sub = s2)
       then aux (pred i) (succ n)
       else aux (pred i) (n)
   in
   aux (len1 - len2) 0</lang>

# match2_num "This cloud looks like a camel, \
    that other cloud looks like a llama" "stone" ;;
- : bool * int = (false, 0)
# match2_num "This cloud looks like a camel, \
    that other cloud looks like a llama" "cloud" ;;
- : bool * int = (true, 2)

Oforth

<lang Oforth>func: stringMatching(s1, s2) { | i | 

  s2 isAllAt(s1, 1) ifTrue: [ System.Out s1 << " begins with " << s2 << cr ]
  s2 isAllAt(s1, s1 size s2 size - 1 + ) ifTrue: [ System.Out s1 << " ends with " << s2 << cr ] 

  s1 indexOfAll(s2) ->i
  i ifNotNull: [ System.Out s1 << " includes " << s2 << " at position : " << i << cr ]

  "\nAll positions : " println 
  1 ->i
  while (s1 indexOfAllFrom(s2, i) dup ->i notNull) [
     System.Out s1 << " includes " << s2 << " at position : " << i << cr
     i s2 size + ->i
     ]

}</lang>

Output:
>stringMatching("arduinoardblobard", "ard")
arduinoardblobard begins with ard
arduinoardblobard ends with ard
arduinoardblobard includes ard at position : 1

All positions :
arduinoardblobard includes ard at position : 1
arduinoardblobard includes ard at position : 8
arduinoardblobard includes ard at position : 15

OxygenBasic

<lang oxygenbasic> string s="sdfkjhgsdfkdfgkbopefioqwurti487sdfkrglkjfs9wrtgjglsdfkdkjcnmmb.,msfjflkjsdfk"

string f="sdfk"

string cr=chr(13)+chr(10),tab=chr(9)

string pr="FIND STRING LOCATIONS" cr cr

sys a=0, b=1, count=0, ls=len(s), lf=len(f)

do 

 a=instr b,s,f
 if a=0 then exit do
 count++
 if a=1 then  pr+="Begins with keyword" cr
 pr+=count tab a cr
 if a=ls-lf+1 then pr+="Ends with keyword at " a cr
 b=a+1

end do

pr+=cr "Total matches: " count cr

print pr

'FIND STRING LOCATIONS ' 'Begins with keyword '1 1 '2 8 '3 32 '4 51 '5 73 'Ends with keyword at 73 ' 'Total matches: 5 </lang>

PARI/GP

This meets the first but not the second of the optional requirements. Note that GP treats any nonzero value as true so the location found by contains() can be ignore if not needed. <lang parigp>startsWith(string, prefix)={ 

 string=Vec(string);
 prefix=Vec(prefix);
 if(#prefix > #string, return(0));
 for(i=1,#prefix,if(prefix[i]!=string[i], return(0)));
 1

}; contains(string, inner)={ 

 my(good);
 string=Vec(string);
 inner=Vec(inner);
 for(i=0,#string-#inner,
   good=1;
   for(j=1,#inner,
     if(inner[j]!=string[i+j], good=0; break)
   );
   if(good, return(i+1))
 );
 0

}; endsWith(string, suffix)={ 

 string=Vec(string);
 suffix=Vec(suffix);
 if(#suffix > #string, return(0));
 for(i=1,#suffix,if(prefix[i]!=string[i+#string-#suffix], return(0)));
 1

};</lang>

Perl

Using regexes:

<lang perl>$str1 =~ /^\Q$str2\E/ # true if $str1 starts with $str2 $str1 =~ /\Q$str2\E/ # true if $str1 contains $str2 $str1 =~ /\Q$str2\E$/ # true if $str1 ends with $str2</lang>

Using index:

<lang perl>index($str1, $str2) == 0 # true if $str1 starts with $str2 index($str1, $str2) != -1 # true if $str1 contains $str2 rindex($str1, $str2) == length($str1) - length($str2) # true if $str1 ends with $str2</lang>

Using substr:

<lang perl>substr($str1, 0, length($str2)) eq $str2 # true if $str1 starts with $str2 substr($str1, - length($str2)) eq $str2 # true if $str1 ends with $str2</lang>

Bonus task (printing all positions where $str2 appears in $str1):

<lang perl>print $-[0], "\n" while $str1 =~ /\Q$str2\E/g; # using a regex</lang> <lang perl>my $i = -1; print $i, "\n" while ($i = index $str1, $str2, $i + 1) != -1; # using index</lang>

Perl 6

<lang perl6>my @subs = ( 

   # Regex-based:
   sub R_contains    ( Str $_, Str $s2 ) { ? m/   $s2   / },
   sub R_starts_with ( Str $_, Str $s2 ) { ? m/ ^ $s2   / },
   sub R_ends_with   ( Str $_, Str $s2 ) { ? m/   $s2 $ / },

   # Index-based:
   sub I_contains    ( Str $_, Str $s2 ) {         .index( $s2)\   .defined },
   sub I_starts_with ( Str $_, Str $s2 ) { my $m = .index( $s2); $m.defined and $m == 0 },
   sub I_ends_with   ( Str $_, Str $s2 ) { my $m = .rindex($s2); $m.defined and $m == .chars - $s2.chars },

   # Substr-based:
   sub S_starts_with ( Str $_, Str $s2 ) { .substr(0, $s2.chars) eq $s2 },
   sub S_ends_with   ( Str $_, Str $s2 ) { .substr(  -$s2.chars) eq $s2 },

   # Optional tasks:
   sub R_find        ( Str $_, Str $s2 ) { $/.from if /$s2/ },
   sub R_find_all    ( Str $_, Str $s2 ) {
       my @p = .match: /$s2/, :g;
       @p».from if @p;
   },

);

my $str1 = 'abcbcbcd'; my @str2s = < ab bc cd zz >;

say "'$str1' vs:".fmt('%15s '), @str2s.fmt('%-15s'); for [1, 4, 6], [2, 5, 7], [0, 3], [8, 9] { 

   say;
   for @subs[.list] -> $sub {
       say "{$sub.name}:".fmt('%15s '),
           @str2s.map({ ~$sub.($str1, $_) }).fmt('%-15s');
   }

}</lang>

Output:
 'abcbcbcd' vs: ab              bc              cd              zz             

 R_starts_with: Bool::True      Bool::False     Bool::False     Bool::False    
 I_starts_with: Bool::True      Bool::False     Bool::False     Bool::False    
 S_starts_with: Bool::True      Bool::False     Bool::False     Bool::False    

   R_ends_with: Bool::False     Bool::False     Bool::True      Bool::False    
   I_ends_with: Bool::False     Bool::False     Bool::True      Bool::False    
   S_ends_with: Bool::False     Bool::False     Bool::True      Bool::False    

    R_contains: Bool::True      Bool::True      Bool::True      Bool::False    
    I_contains: Bool::True      Bool::True      Bool::True      Bool::False    

        R_find: 0               1               6               Nil()          
    R_find_all: 0               1 3 5           6               Nil()

PHP

<lang php><?php /**********************************************************************************

  • This program gets needle and haystack from the caller (chm.html) (see below)
  • and checks for occurrences of the needle in the haystack
  • 02.05.2013 Walter Pachl
  • Comments or Suggestions welcome
                                                                                                                                                                    • /

$haystack = $_POST['haystack']; if ($haystack==) {$haystack='no haystack given';} $needle = $_POST['needle']; if ($needle==) {$needle='no needle given';}

function rexxpos($h,$n) { 

 $pos = strpos($h,$n);
 if ($pos === false) { $pos=-1; }
 else                { $pos=$pos+1; }
 return ($pos);
}

$pos=rexxpos($haystack,$needle); $tx1 = ""; if ($pos==-1){ $n=0; } // not found else { $n=1; } // found once (so far) // Special cases if ($pos==1){ $tx1="needle found to be the start of the haystack"; } if ($pos==strlen($haystack)-strlen($needle)+1) 

           { $tx1="needle found at end of haystack"; }

if ($n>0) { // look for other occurrences 

 $pl=$pos; // list of positions
 $p=$pos;  //
 $x="*************************************";
 $h=$haystack;
 while ($p>0) {
   $h=substr($x,0,$p).substr($h,$p);
   $p=rexxpos($h,$needle);
   if ( $p>0 ) { $n=$n+1; $pl=$pl.", ".$p; }
 }
      if ($n==1) { $txt="needle found once in haystack, position: $pl."; }
 else if ($n==2) { $txt="needle found twice in haystack, position(s): $pl."; }
 else            { $txt="needle found $n times in haystack, position(s): $pl."; }

} else { $txt="needle not found in haystack."; } ?> <html> 

 <head>
   <title>Character Matching</title>
   <meta name="author" content="Walter Pachl">
   <meta name="date" content="02.05.2013">
   <style>
     p { font: 120% courier; }
   </style>
 </head>
 <body>

Haystack: '<?php echo "$haystack" ?>'

Needle:   '<?php echo "$needle" ?>'

<?php echo "$txt" ?>

<?php echo "$tx1" ?>

 </body>

</html></lang> <lang php><?php <!DOCTYPE html> <html> 

 <head>
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
   <title>Character matching</title>
 </head>
 <body>
   <form id="test" name="test" method="post" action="chmx.php">

Character matching

Given two strings, demonstrate the following 3 types of matchings:

  1. Determining if the first string starts with second string
  2. Determining if the first string contains the second string at any location
  3. Determining if the first string ends with the second string

Optional requirements:

  1. Print the location of the match(es) for part 2
  2. Handle multiple occurrences of a string for part 2.

Haystack: <input type="text" name="haystack" size="80">

Needle:   <input type="text" name="needle" size="80">

Press <input name="Submit" type="submit" class="erfolg" value="CHECK"/> to invoke chmx.php.

 </form>
 </body>

</html></lang>

PicoLisp

<lang PicoLisp>: (pre? "ab" "abcd") -> "abcd"

(pre? "xy" "abcd")

-> NIL

(sub? "bc" "abcd")

-> "abcd"

(sub? "xy" "abcd")

-> NIL

(tail (chop "cd") (chop "abcd"))

-> ("c" "d")

(tail (chop "xy") (chop "abcd"))

-> NIL


(de positions (Pat Str) 

  (setq Pat (chop Pat))
  (make
     (for ((I . L) (chop Str) L (cdr L))
        (and (head Pat L) (link I)) ) ) )
(positions "bc" "abcdabcd")

-> (2 6)</lang>

PL/I

<lang PL/I> /* Let s be one string, t be the other that might exist within s. */ 

                                                    /* 8-1-2011 */

k = index(s, t); if k = 0 then put skip edit (t, ' is nowhere in sight') (a); else if k = 1 then 

  put skip edit (t, '  starts at the beginning of  ', s) (a);

else if k+length(t)-1 = length(s) then 

  put skip edit (t, '  is at the end of  ', s) (a);

else put skip edit (t, ' is within ', s) (a);

if k > 0 then put skip edit (t, ' starts at position ', k) (a); </lang>

Optional extra:

<lang PL/I> /* Handle multiple occurrences. */ 

  n = 1;
  do forever;
     k = index(s, t, n);
     if k = 0 then
        do;
           if n = 1 then put skip list (t, ' is nowhere in sight');
           stop;
        end;
     else if k = 1 then
        put skip edit ('<', t, '> starts at the beginning of  ', s) (a);
     else if k+length(t)-1 = length(s) then
        put skip edit ('<', t, '> is at the end of  ', s) (a);
     else put skip edit ('<', t, '> is within  ', s) (a);
     n =   k + length(t);

     if k > 0 then
        put skip edit ('<', t, '> starts at position ', trim(k)) (a);
     else stop;
  end;

</lang>

PureBasic

<lang PureBasic>Procedure StartsWith(String1$, String2$) 

 Protected Result
 If FindString(String1$, String2$, 1) =1 ; E.g Found in possition 1
   Result =CountString(String1$, String2$)
 EndIf
 ProcedureReturn Result

EndProcedure

Procedure EndsWith(String1$, String2$) 

 Protected Result, dl=Len(String1$)-Len(String2$)
 If dl>=0 And Right(String1$, Len(String2$))=String2$
   Result =CountString(String1$, String2$)
 EndIf
 ProcedureReturn Result

EndProcedure</lang> And a verification <lang PureBasic>If OpenConsole() 

 PrintN(Str(StartsWith("Rosettacode", "Rosetta")))           ; = 1
 PrintN(Str(StartsWith("Rosettacode", "code")))              ; = 0
 PrintN(Str(StartsWith("eleutherodactylus cruralis", "e")))  ; = 3
 PrintN(Str(EndsWith  ("Rosettacode", "Rosetta")))  ; = 0
 PrintN(Str(EndsWith  ("Rosettacode", "code")))     ; = 1
 PrintN(Str(EndsWith  ("Rosettacode", "e")))        ; = 2
 
 Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input()
 CloseConsole()

EndIf</lang>

An alternate and more complete solution: <lang PureBasic>Procedure startsWith(string1$, string2$) 

 ;returns one if string1$ starts with string2$, otherwise returns zero
 If FindString(string1$, string2$, 1) = 1
   ProcedureReturn 1
 EndIf 
 ProcedureReturn 0

EndProcedure

Procedure contains(string1$, string2$, location = 0) 

 ;returns the location of the next occurrence of string2$ in string1$ starting from location,
 ;or zero if no remaining occurrences of string2$ are found in string1$
 ProcedureReturn FindString(string1$, string2$, location + 1)

EndProcedure

Procedure endsWith(string1$, string2$) 

 ;returns one if string1$ ends with string2$, otherwise returns zero
 Protected ls = Len(string2$)
 If Len(string1$) - ls >= 0 And Right(string1$, ls) = string2$
   ProcedureReturn 1
 EndIf
 ProcedureReturn 0

EndProcedure

If OpenConsole() 

 PrintN(Str(startsWith("RosettaCode", "Rosetta")))           ; = 1, true
 PrintN(Str(startsWith("RosettaCode", "Code")))              ; = 0, false
 
 PrintN("")
 PrintN(Str(contains("RosettaCode", "luck")))                ; = 0, no occurrences
 Define location
 Repeat
   location = contains("eleutherodactylus cruralis", "e", location)
   PrintN(Str(location))                                     ;display each occurrence: 1, 3, 7,  & 0 (no more occurrences)
 Until location = 0
 
 PrintN("")
 PrintN(Str(endsWith  ("RosettaCode", "Rosetta")))            ; = 0, false
 PrintN(Str(endsWith  ("RosettaCode", "Code")))               ; = 1, true
  
 Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input()
 CloseConsole()

EndIf</lang>

Output:
1
0

0
1
3
7
0

0
1

PowerShell

<lang Powershell> "spicywiener".StartsWith("spicy") "spicywiener".Contains("icy") "spicywiener".EndsWith("wiener") "spicywiener".IndexOf("icy") [regex]::Matches("spicywiener", "i").count </lang>

Output:
True
True
True
2
2

Python

<lang python>"abcd".startswith("ab") #returns True "abcd".endswith("zn") #returns False "bb" in "abab" #returns False "ab" in "abab" #returns True loc = "abab".find("bb") #returns -1 loc = "abab".find("ab") #returns 0 loc = "abab".find("ab",loc+1) #returns 2</lang>

Racket

<lang racket>

  1. lang racket

(require srfi/13) (string-prefix? "ab" "abcd") (string-suffix? "cd" "abcd") (string-contains "abab" "bb") (string-contains "abab" "ba") </lang>

Output:
#t
#t
#f
1


Retro

<lang Retro>: startsWith? ( $1 $2 - f ) 

 withLength &swap dip 0 swap ^strings'getSubset compare ;

"abcdefghijkl" "abcde" startsWith? "abcdefghijkl" "bcd" startsWith?

"abcdefghijkl" "bcd" ^strings'search "abcdefghijkl" "zmq" ^strings'search

endsWith? ( $1 $2 - f )
 swap withLength + over getLength - compare ;

"abcdefghijkl" "ijkl" endsWith? "abcdefghijkl" "abc" endsWith?</lang>

REXX

Extra coding was added to take care of using plurals in the output messages. <lang rexx>/*REXX program demonstrates some basic character string testing. */ parse arg a b /*obtain A and B from the C.L. */ say 'string A = ' a /*display string A to terminal.*/ say 'string B = ' b /* " " B " " */ say if left(A,length(b))==b then say 'string A starts with string B' 

                        else say "string  A  doesn't start with string  B"

say 

                          /*another method,  however a wee bit obtuse. */

/*¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬ if compare(a,b)==length(b) then say 'string A starts with string B' 

                          else say "string A doesn't start with string B"

¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬*/ 

                                      /* [↑]  above is a big comment.  */

p=pos(b,a) if p==0 then say "string A doesn't contain string B" 

        else say 'string  A  contains string  B  (starting in position' p")"

say if right(A,length(b))==b then say 'string A ends with string B' 

                         else say "string  A  doesn't end with string  B"

say Ps=; p=0; do until p==0 

                                p=pos(b, a, p+1)
                                if p\==0  then Ps = Ps',' p
                                end   /*until ···*/

Ps=space(strip(Ps, 'L', ",")) times=words(Ps) if times==0 then say "string A doesn't contain string B" 

            else say 'string  A  contains string  B ',
                       times   'time'left('s',times>1),
                      "(at position"left('s', times>1)   Ps')'

                                      /*stick a fork in it, we're done.*/</lang>
Output:

when the following is specified (five Marx brothers)

  Chico_Harpo_Groucho_Zeppo_Gummo p 
string  A  =  Chico_Harpo_Groucho_Zeppo_Gummo
string  B  =  p

string  A  doesn't start with string B

string  A  contains string  B  (starting in position 10)

string  A  doesn't end with string B

string  A  contains string  B  3 times (at positions 10, 23, 24)
Output:

when the following is specified

  Chico_Harpo_Groucho_Zeppo_Gummo Z 
string  A  =  Chico_Harpo_Groucho_Zeppo_Gummo
string  B  =  Z

string  A  doesn't start with string  B

string  A  contains string  B  (starting in position 21)

string  A  doesn't end with string  B

string  A  contains string  B  1 time (at position 21)
Output:

when the following is specified

  Chico_Harpo_Groucho_Zeppo_Gummo Chi 
string  A  =  Chico_Harpo_Groucho_Zeppo_Gummo
string  B  =  Chi

string  A  starts with string  B

string  A  contains string B  (starting in position 1)
 
string  A  doesn't end with string  B

string  A  contains string  B  1 time (at position 1)
Output:

when the following is specified

  Chico_Harpo_Groucho_Zeppo_Gummo mmo 
string  A  =  Chico_Harpo_Groucho_Zeppo_Gummo
string  B  =  mmo

string  A  doesn't start with string  B

string  A  contains string  B  (starting in position 29)

string  A  ends with string  B

string  A  contains string  B  1 time (at position 29)

Ruby

<lang ruby>p 'abcd'.start_with?('ab') #returns true p 'abcd'.end_with?('ab') #returns false p 'abab'.include?('bb') #returns false p 'abab'.include?('ab') #returns true p 'abab'['bb'] #returns nil p 'abab'['ab'] #returns "ab" p 'abab'.index('bb') #returns nil p 'abab'.index('ab') #returns 0 p 'abab'.index('ab', 1) #returns 2 p 'abab'.rindex('ab') #returns 2</lang>

Run BASIC

<lang runbasic>s1$ = "abc def ghi klmnop" s2$ = "abc" ' begins with s3$ = "ef" ' is in the string s4$ = "nop" ' ends with

sn2$ = "abcx" ' not begins with sn3$ = "efx" ' not in the string sn4$ = "nopx" ' not ends with

if left$(s1$,len(s2$)) <> s2$ then a$ = "Not " print "String:";s1$;" does ";a$;"begin with:";s2$

if instr(s1$,s3$) = 0 then a$ = "Not " print "String:";s1$;" does ";a$;"contain:";s3$

if mid$(s1$,len(s1$) + 1 - len(s4$),len(s4$)) <> s4$ then a$ = "Not " print "String:";s1$;" does ";a$;"end with:";s4$

' ----------- not ----------------------------- print if left$(s1$,len(sn2$)) <> sn2$ then a$ = "Not " print "String:";s1$;" does ";a$;"begin with:";sn2$

if instr(s1$,sn3$) = 0 then a$ = "Not " print "String:";s1$;" does ";a$;"contain:";sn3$

if mid$(s1$,len(s1$) + 1 - len(sn4$),len(sn4$)) <> sn4$ then a$ = "Not " print "String:";s1$;" does ";a$;"end with:";sn4$</lang>

Output:
String:abc def ghi klmnop does begin with:abc
String:abc def ghi klmnop does contain:ef
String:abc def ghi klmnop does end with:nop

String:abc def ghi klmnop does Not begin with:abcx
String:abc def ghi klmnop does Not contain:efx
String:abc def ghi klmnop does Not end with:nopx

Scala

<lang scala>"abcd".startsWith("ab") //returns true "abcd".endsWith("zn") //returns false "abab".contains("bb") //returns false "abab".contains("ab") //returns true

var loc="abab".indexOf("bb") //returns -1 loc = "abab".indexOf("ab") //returns 0 loc = "abab".indexOf("ab", loc+1) //returns 2</lang>

Seed7

<lang seed7>$ include "seed7_05.s7i";

const proc: main is func 

 local
   var integer: position is 0;
 begin
   writeln(startsWith("abcd", "ab")); # write TRUE
   writeln(endsWith("abcd", "zn"));   # write FALSE
   writeln(pos("abab", "bb") <> 0);   # write FALSE
   writeln(pos("abab", "ab") <> 0);   # write TRUE
   writeln(pos("abab", "bb"));        # write 0
   position := pos("abab", "ab");
   writeln(position);                 # position is 1
   position := pos("abab", "ab", succ(position));
   writeln(position);                 # position is 3
 end func;</lang>
Output:
TRUE
FALSE
FALSE
TRUE
0
1
3

Sidef

<lang ruby>var first = "abc-abcdef-abcd"; var second = "abc";

say first.begins_with(second); #=> true say first.contains(second); #=> true say first.ends_with(second); #=> false

  1. Get and print the location of the match

say first.index(second); #=> 0

  1. Find multiple occurrences of a string

var pos = -1; while (pos = first.index(second, pos+1) != -1) { 

   say "Match at pos: #{pos}";

}</lang>

Smalltalk

<lang smalltalk>a startsWith: b a includesSubCollection: b a endsWith: b a indexOfSubCollection: b a indexOfSubCollection: b startingAt: pos</lang>

Standard ML

<lang sml>String.isPrefix "ab" "abcd"; (* returns true *) String.isSuffix "zn" "abcd"; (* returns false *) String.isSubstring "bb" "abab"; (* returns false *) String.isSubstring "ab" "abab"; (* returns true *)

  1. 2 (Substring.base (#2 (Substring.position "bb" (Substring.full "abab")))); (* returns 4 *)

val loc = #2 (Substring.base (#2 (Substring.position "ab" (Substring.full "abab")))); (* returns 0 *) val loc' = #2 (Substring.base (#2 (Substring.position "ab" (Substring.extract ("abab", loc+1, NONE))))); (* returns 2 *)</lang>

Tcl

In this code, we are looking in various ways for the string in the variable needle in the string in the variable haystack. <lang tcl>set isPrefix [string equal -length [string length $needle] $haystack $needle] set isContained [expr {[string first $needle $haystack] >= 0}] set isSuffix [string equal $needle [string range $haystack end-[expr {[string length $needle]-1}] end]]</lang>

Of course, in the cases where the needle is a glob-safe string (i.e., doesn't have any of the characters “*?[\” in), this can be written far more conveniently: <lang tcl>set isPrefix [string match $needle* $haystack] set isContained [string match *$needle* $haystack] set isSuffix [string match *$needle $haystack]</lang>

Another powerful technique is to use the regular expression engine in literal string mode: <lang tcl>set isContained [regexp ***=$needle $haystack]</lang> This can be extended by getting the regexp to return the locations of the matches, enabling the other forms of match to be done: <lang tcl>set matchLocations [regexp -indices -all -inline ***=$needle $haystack]

  1. Each match location is a pair, being the index into the string where the needle started
  2. to match and the index where the needle finished matching

set isContained [expr {[llength $matchLocations] > 0}] set isPrefix [expr {[lindex $matchLocations 0 0] == 0}] set isSuffix [expr {[lindex $matchLocations end 1] == [string length $haystack]-1}] set firstMatchStart [lindex $matchLocations 0 0] puts "Found \"$needle\" in \"$haystack\" at $firstMatchStart" foreach location $matchLocations { 

   puts "needle matched at index [lindex $location 0]"

}</lang>

TUSCRIPT

<lang tuscript> $$ MODE TUSCRIPT ASK "string1", string1="" ASK "string2", string2=""

IF (string1.sw.string2) THEN PRINT string1," starts with ",string2 ELSE PRINT string1," not starts with ",string2 ENDIF SET beg=STRING (string1,string2,0,0,0,end) IF (beg!=0) THEN PRINT string1," contains ",string2 PRINT " starting in position ",beg PRINT " ending in position ",end ELSE PRINT string1," not contains ",string2 ENDIF

IF (string1.ew.string2) THEN PRINT string1," ends with ",string2 ELSE PRINT string1," not ends with ",string2 ENDIF </lang>

Output:
string1 >Rosetta Code
string2 >Code
Rosetta Code not starts with Code
Rosetta Code contains        Code
  starting in position 9
  ending   in position 13
Rosetta Code ends with       Code

TXR

TXR Lisp

<lang txr>@(do 

  (tree-case *args*
    ((big small)
       (cond
         ((< (length big) (length small))
          (put-line `@big is shorter than @small`))
         ((str= big small)
          (put-line `@big and @small are equal`))
         ((match-str big small)
          (put-line `@small is a prefix of @big`))
         ((match-str big small -1)
          (put-line `@small is a suffix of @big`))
         (t (let ((pos (search-str big small)))
              (if pos
                (put-line `@small occurs in @big at position @pos`)
                (put-line `@small does not occur in @big`))))))
    (otherwise
      (put-line `usage: @(ldiff *full-args* *args*) <bigstring> <smallstring>`))))</lang>
Output:
$ txr cmatch2.txr x
usage: txr cmatch2.txr <bigstring> <smallstring>
$ txr cmatch2.txr x y z
usage: txr cmatch2.txr <bigstring> <smallstring>
$ txr cmatch2.txr catalog cat
cat is a prefix of catalog
$ txr cmatch2.txr catalog log
log is a suffix of catalog
$ txr cmatch2.txr catalog at
at occurs in catalog at position 1
$ txr cmatch2.txr catalog catalogue
catalog is shorter than catalogue
$ txr cmatch2.txr catalog catalog
catalog and catalog are equal
$ txr cmatch2.txr catalog dog
dog does not occur in catalog

Pattern Language

<lang txr>@line @(cases) @ line @ (output) second line is the same as first line @ (end) @(or) @ (skip)@line @ (output) first line is a suffix of the second line @ (end) @(or) @ line@(skip) @ (output) first line is a suffix of the second line @ (end) @(or) @ prefix@line@(skip) @ (output) first line is embedded in the second line at position @(length prefix) @ (end) @(or) @ (output) first line is not found in the second line @ (end) @(end)</lang>

Output:
$ txr cmatch.txr -
123
01234
first line is embedded in the second line at position 1
$ txr cmatch.txr -
123
0123
first line is a suffix of the second line

VBScript

<lang vb>Function StartsWith(s1,s2) StartsWith = False If Left(s1,Len(s2)) = s2 Then StartsWith = True End If End Function

Function Contains(s1,s2) Contains = False If InStr(1,s1,s2) Then Contains = True & " at positions " j = 1 Do Until InStr(j,s1,s2) = False Contains = Contains & InStr(j,s1,s2) & ", " If j = 1 Then If Len(s2) = 1 Then j = j + InStr(j,s1,s2) Else j = j + (InStr(j,s1,s2) + (Len(s2) - 1)) End If Else If Len(s2) = 1 Then j = j + ((InStr(j,s1,s2) - j) + 1) Else j = j + ((InStr(j,s1,s2) - j) + (Len(s2) - 1)) End If End If Loop End If End Function

Function EndsWith(s1,s2) EndsWith = False If Right(s1,Len(s2)) = s2 Then EndsWith = True End If End Function

WScript.StdOut.Write "Starts with test, 'foo' in 'foobar': " & StartsWith("foobar","foo") WScript.StdOut.WriteLine WScript.StdOut.Write "Contains test, 'o' in 'fooooobar': " & Contains("fooooobar","o") WScript.StdOut.WriteLine WScript.StdOut.Write "Ends with test, 'bar' in 'foobar': " & EndsWith("foobar","bar")</lang>

Output:

Starts with test, 'foo' in 'foobar': True
Contains test, 'o' in 'fooooobar': True at positions 2, 3, 4, 5, 6, 
Ends with test, 'bar' in 'foobar': True

XPL0

<lang XPL0>include c:\cxpl\codes; \intrinsic 'code' declarations string 0; \use zero-terminated strings

func StrLen(A); \Return number of characters in a string char A; int I; for I:= 0 to -1>>1-1 do 

   if A(I) = 0 then return I;

func StrFind(A, B); \Search for string B in string A \Returns index of first occurrence of string B in A, or -1 if B is not found char A, B; \strings to be compared int LA, LB, I, J; [LA:= StrLen(A); 

LB:= StrLen(B);
for I:= 0 to LA-LB do
   [for J:= 0 to LB-1 do
       if B(J) # A(J+I) then J:= LB+1;
   if J = LB then return I;    \found
   ];

return -1; ];

char Str; int I, J; [Str:= "pack my box with"; \ 0123456789012345 Text(0, if StrFind(Str, "pack") = 0 then "yes" else "no"); CrLf(0); \1. Text(0, if StrFind(Str, "ack") = 0 then "yes" else "no"); CrLf(0); I:= StrFind(Str, "x w"); Text(0, if I >= 0 then "yes" else "no"); \2. Text(0, ", at offset "); IntOut(0, I); CrLf(0); I:= 0; J:= 0; \offsets of space characters loop [I:= StrFind(Str+J, " "); 

       if I < 0 then quit;
       IntOut(0, I+J); ChOut(0, ^ );
       J:= J+I+1;
       ];

CrLf(0); Text(0, if StrFind(Str, "X w") >= 0 then "yes" else "no"); CrLf(0); Text(0, if StrFind(Str, "with") = StrLen(Str)-StrLen("with") then "yes" else "no"); CrLf(0); \3. Text(0, if StrFind(Str, "x w" ) = StrLen(Str)-StrLen("x w" ) then "yes" else "no"); CrLf(0); ]</lang>

Output:
yes
no
yes, at offset 10
4 7 11 
no
yes
no

zkl

<lang zkl>fcn f(text,p){ if(text.find(p)==0)println("Yep") else println("Nope") } f("foobar","foo") //--> Yep f("foobar","bar") //--> Nope</lang> <lang zkl>fcn f(text,p){ if(Void!=(n:=text.find(p)))println("Contained @",n) else println("Nope") } f("foobar","ob") //--> Contained @2 f("foobar","food") //--> Nope</lang> <lang zkl>fcn f(text,p){ 

  if( Void!=(n:=text.rfind(p)) and n+p.len()==text.len() )
     println("tail gunner") else println("Nope")

} f("foobar","r"); f("foobar","ar"); //--> tail gunners f("foobar","ob"); //--> Nope f("foobarfoobar","bar"); //--> tail gunner</lang>

Retrieved from "https://rosettacode.org/wiki/String_matching?oldid=160754"