Substring/Top and tail: Difference between revisions
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=={{header|UNIX Shell}}== |
=={{header|UNIX Shell}}== |
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⚫ | |||
First ''or'' last character: |
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<lang bash> |
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#!/bin/zsh |
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str='abcdefg' |
<lang bash>str='abcdefg' |
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echo ${str#?} # Remove first char |
echo "${str#?}" # Remove first char |
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echo ${str%?} # Remove last char |
echo "${str%?}" # Remove last char</lang> |
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⚫ | |||
First ''and'' last character: |
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</lang> |
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⚫ | |||
⚫ | |||
: bash and ksh, use substring expansion, from character index 1 for length of (string length) minus 2 |
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: <lang bash>echo "${s:1:${#s}-2}"</lang> |
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: POSIX shells like dash, need a temp variable |
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: <lang bash>tmp=${s#?}; tmp=${tmp%?}; echo "$tmp"</lang> |
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=={{header|Vala}}== |
=={{header|Vala}}== |
Revision as of 17:00, 19 October 2018
You are encouraged to solve this task according to the task description, using any language you may know.
The task is to demonstrate how to remove the first and last characters from a string.
The solution should demonstrate how to obtain the following results:
- String with first character removed
- String with last character removed
- String with both the first and last characters removed
If the program uses UTF-8 or UTF-16, it must work on any valid Unicode code point, whether in the Basic Multilingual Plane or above it.
The program must reference logical characters (code points), not 8-bit code units for UTF-8 or 16-bit code units for UTF-16.
Programs for other encodings (such as 8-bit ASCII, or EUC-JP) are not required to handle all Unicode characters.
360 Assembly
<lang 360asm>* Substring/Top and tail 04/03/2017 SUBSTRTT CSECT
USING SUBSTRTT,R13 base register B 72(R15) skip savearea DC 17F'0' savearea STM R14,R12,12(R13) save previous context ST R13,4(R15) link backward ST R15,8(R13) link forward LR R13,R15 set addressability
XPRNT S8,L'S8 print s8 MVC S7,S8+1 s7=substr(s8,2,7) XPRNT S7,L'S7 print s7 MVC S7,S8 s7=substr(s8,1,7) XPRNT S7,L'S7 print s7 MVC S6,S8+1 s6=substr(s8,2,6) XPRNT S6,L'S6 print s6
L R13,4(0,R13) epilog LM R14,R12,12(R13) restore previous context XR R15,R15 rc=0 BR R14 exit
S8 DC CL8'12345678' S7 DS CL7 S6 DS CL6
YREGS END SUBSTRTT</lang>
- Output:
12345678 2345678 1234567 234567
ACL2
<lang Lisp>(defun str-rest (str)
(coerce (rest (coerce str 'list)) 'string))
(defun rdc (xs)
(if (endp (rest xs)) nil (cons (first xs) (rdc (rest xs)))))
(defun str-rdc (str)
(coerce (rdc (coerce str 'list)) 'string))
(str-rdc "string") (str-rest "string") (str-rest (str-rdc "string"))</lang>
Ada
<lang Ada>with Ada.Text_IO;
procedure Remove_Characters is
S: String := "upraisers"; use Ada.Text_IO;
begin
Put_Line("Full String: """ & S & """"); Put_Line("Without_First: """ & S(S'First+1 .. S'Last) & """"); Put_Line("Without_Last: """ & S(S'First .. S'Last-1) & """"); Put_Line("Without_Both: """ & S(S'First+1 .. S'Last-1) & """");
end Remove_Characters;</lang>
Output:
Full String: "upraisers" Without_First: "praisers" Without_Last: "upraiser" Without_Both: "praiser"
With UTF8 support in Ada 2012 (Wide_Character of literals is automatic):
<lang Ada>with Ada.Text_IO; with Ada.Strings.UTF_Encoding.Wide_Strings;
procedure Remove_Characters is
use Ada.Text_IO; use Ada.Strings.UTF_Encoding; use Ada.Strings.UTF_Encoding.Wide_Strings; S : String := "upraisers"; U : Wide_String := Decode (UTF_8_String'(S)); function To_String (X : Wide_String)return String is begin return String (UTF_8_String'(Encode (X))); end To_String;
begin
Put_Line (To_String ("Full String: """ & U & """")); Put_Line (To_String ("Without_First: """ & U (U'First + 1 .. U'Last) & """")); Put_Line (To_String ("Without_Last: """ & U (U'First .. U'Last - 1) & """")); Put_Line (To_String ("Without_Both: """ & U (U'First + 1 .. U'Last - 1) & """"));
end Remove_Characters;</lang>
Output:
Full String: "upraisers" Without_First: "praisers" Without_Last: "upraiser" Without_Both: "praiser"
Aime
<lang aime>o_text(delete("knights", 0)); o_newline(); o_text(delete("knights", -1)); o_newline(); o_text(delete(delete("knights", 0), -1)); o_newline();</lang>
- Output:
nights knight night
Apex
<lang java> String strOrig = 'brooms'; String str1 = strOrig.substring(1, strOrig.length()); system.debug(str1); String str2 = strOrig.substring(0, strOrig.length()-1); system.debug(str2); String str3 = strOrig.substring(1, strOrig.length()-1); system.debug(str3);
// Regular Expressions approach String strOrig = 'brooms'; String str1 = strOrig.replaceAll( '^.', ); system.debug(str1); String str2 = strOrig.replaceAll( '.$', ) ; system.debug(str2); String str3 = strOrig.replaceAll( '^.|.$', ); system.debug(str3); </lang>
- Output:
rooms broom room
ALGOL 68
<lang algol68>#!/usr/local/bin/a68g --script #
STRING str="upraisers"; printf(($gl$,
str, # remove no characters # str[LWB str+1: ], # remove the first character # str[ :UPB str-1], # remove the last character # str[LWB str+1:UPB str-1], # remove both the first and last character # str[LWB str+2: ], # remove the first 2 characters # str[ :UPB str-2], # remove the last 2 characters # str[LWB str+1:UPB str-2], # remove 1 before and 2 after # str[LWB str+2:UPB str-1], # remove 2 before and one after # str[LWB str+2:UPB str-2] # remove both the first and last 2 characters #
))</lang> Output:
upraisers praisers upraiser praiser raisers upraise praise raiser raise
AutoHotkey
<lang AutoHotkey>myString := "knights" MsgBox % SubStr(MyString, 2) MsgBox % SubStr(MyString, 1, StrLen(MyString)-1) MsgBox % SubStr(MyString, 2, StrLen(MyString)-2)</lang>
AWK
<lang awk>BEGIN {
mystring="knights" print substr(mystring,2) # remove the first letter print substr(mystring,1,length(mystring)-1) # remove the last character print substr(mystring,2,length(mystring)-2) # remove both the first and last character
}</lang>
BASIC
<lang basic>10 PRINT FN F$("KNIGHTS"): REM STRIP THE FIRST LETTER 20 PRINT FN L$("SOCKS"): REM STRIP THE LAST LETTER 30 PRINT FN B$("BROOMS"): REM STRIP BOTH THE FIRST AND LAST LETTER 100 END
9000 DEF FN F$(A$)=RIGHT$(A$,LEN(A$)-1) 9010 DEF FN L$(A$)=LEFT$(A$,LEN(A$)-1) 9020 DEF FN B$(A$)=FN L$(FN F$(A$))</lang>
Sinclair ZX81 BASIC
Note that strings are indexed from 1. <lang basic>10 REM STRING SLICING EXAMPLE 20 LET S$="KNIGHTS" 30 REM WITH FIRST CHARACTER REMOVED: 40 PRINT S$(2 TO ) 50 REM WITH LAST CHARACTER REMOVED: 60 PRINT S$( TO LEN S$-1) 70 REM WITH BOTH REMOVED: 80 PRINT S$(2 TO LEN S$-1)</lang>
- Output:
NIGHTS KNIGHT NIGHT
Bracmat
Bracmat uses UTF-8 internally. The function utf
fails if its argument isn't a valid UTF-8 multibyte string, but in two slightly different ways: an indefinite and a definite way. If the argument does not have the required number of bytes but otherwise seems to be ok, Bracmat's backtacking mechanism lenghtens the argument and then calls utf
again. This is repeated until utf either succeeds or definitely fails. The code is far from efficient.
<lang bracmat>(substringUTF-8=
@( Δημοτική : (%?a&utf$!a) ?"String with first character removed" )
& @( Δημοτική
: ?"String with last character removed" (?z&utf$!z) )
& @( Δημοτική
: (%?a&utf$!a) ?"String with both the first and last characters removed" (?z&utf$!z) )
& out
$ ("String with first character removed:" !"String with first character removed")
& out
$ ("String with last character removed:" !"String with last character removed")
& out
$ ( "String with both the first and last characters removed:" !"String with both the first and last characters removed" ));</lang>
!substringUTF-8 String with first character removed: ημοτική String with last character removed: Δημοτικ String with both the first and last characters removed: ημοτικ
If the string is known to consist of 8-byte characters, we can use a simpler method. Essential are the %
and @
prefixes. The %
prefix matches 1 or more elements (bytes, in the case of string pattern matching), while @
matches 0 or 1 elements. In combination these prefixes match 1 and only 1 byte.
<lang bracmat>(substring-8-bit=
@("8-bit string":%@ ?"String with first character removed")
& @("8-bit string":?"String with last character removed" @) & @( "8-bit string"
: %@ ?"String with both the first and last characters removed" @ )
& out
$ ("String with first character removed:" !"String with first character removed")
& out
$ ("String with last character removed:" !"String with last character removed")
& out
$ ( "String with both the first and last characters removed:" !"String with both the first and last characters removed" ));</lang>
!substring-8-bit String with first character removed: -bit string String with last character removed: 8-bit strin String with both the first and last characters removed: -bit strin
BBC BASIC
<lang bbcbasic> s$ = "Rosetta Code"
PRINT MID$(s$, 2) PRINT LEFT$(s$) PRINT LEFT$(MID$(s$, 2))</lang>
Burlesque
<lang blsq> blsq ) "RosettaCode"[- "osettaCode" blsq ) "RosettaCode"-] 'R blsq ) "RosettaCode"~] "RosettaCod" blsq ) "RosettaCode"[~ 'e blsq ) "RosettaCode"~- "osettaCod" </lang>
C
<lang c>#include <string.h>
- include <stdlib.h>
- include <stdio.h>
int main( int argc, char ** argv ){
const char * str_a = "knight"; const char * str_b = "socks"; const char * str_c = "brooms";
char * new_a = malloc( strlen( str_a ) - 1 ); char * new_b = malloc( strlen( str_b ) - 1 ); char * new_c = malloc( strlen( str_c ) - 2 );
strcpy( new_a, str_a + 1 ); strncpy( new_b, str_b, strlen( str_b ) - 1 ); strncpy( new_c, str_c + 1, strlen( str_c ) - 2 );
printf( "%s\n%s\n%s\n", new_a, new_b, new_c );
free( new_a ); free( new_b ); free( new_c );
return 0;
}</lang>
Result:
night sock room
ANSI C provides little functionality for text manipulation outside of string.h. While a number of libraries for this purpose have been written, this example uses only ANSI C.
C++
<lang cpp>#include <string>
- include <iostream>
int main( ) {
std::string word( "Premier League" ) ; std::cout << "Without first letter: " << word.substr( 1 ) << " !\n" ; std::cout << "Without last letter: " << word.substr( 0 , word.length( ) - 1 ) << " !\n" ; std::cout << "Without first and last letter: " << word.substr( 1 , word.length( ) - 2 ) << " !\n" ; return 0 ;
}</lang> Output:
Without first letter: remier League ! Without last letter: Premier Leagu ! Without first and last letter: remier Leagu !
C#
<lang C sharp> using System;
class Program {
static void Main(string[] args) { string testString = "test"; Console.WriteLine(testString.Substring(1)); Console.WriteLine(testString.Substring(0, testString.Length - 1)); Console.WriteLine(testString.Substring(1, testString.Length - 2)); }
} </lang>
Result:
est tes es
Clojure
<lang clojure>; using substring: user=> (subs "knight" 1) "night" user=> (subs "socks" 0 4) "sock" user=> (.substring "brooms" 1 5) "room"
- using rest and drop-last
user=> (apply str (rest "knight")) "night" user=> (apply str (drop-last "socks")) "sock" user=> (apply str (rest (drop-last "brooms"))) "room"</lang>
Common Lisp
subseq
will signal an error if you provide invalid start or end values.
<lang lisp>> (defvar *str* "∀Ꮺ✤Л◒")
- STR*
> (subseq *str* 1) ; remove first character "Ꮺ✤Л◒" > (subseq *str* 0 (1- (length *str*))) ; remove last character "∀Ꮺ✤Л" > (subseq *str* 1 (1- (length *str*))) ; remove first and last character "Ꮺ✤Л"</lang>
D
Version for ASCII strings or Unicode dstrings: <lang d>import std.stdio;
void main() {
// strip first character writeln("knight"[1 .. $]);
// strip last character writeln("socks"[0 .. $ - 1]);
// strip both first and last characters writeln("brooms"[1 .. $ - 1]);
}</lang>
- Output:
night sock room
Delphi
<lang Delphi>program TopAndTail;
{$APPTYPE CONSOLE}
const
TEST_STRING = '1234567890';
begin
Writeln(TEST_STRING); // full string Writeln(Copy(TEST_STRING, 2, Length(TEST_STRING))); // first character removed Writeln(Copy(TEST_STRING, 1, Length(TEST_STRING) - 1)); // last character removed Writeln(Copy(TEST_STRING, 2, Length(TEST_STRING) - 2)); // first and last characters removed
Readln;
end.</lang>
Eero
<lang objc>#import <Foundation/Foundation.h>
int main()
autoreleasepool
s := 'knight' Log( '%@', s[1 .. s.length-1] ) // strip first character
s = 'socks' Log( '%@', s[0 .. s.length-2] ) // strip last character s = 'brooms' Log( '%@', s[1 .. s.length-2] ) // strip both first and last characters
s = 'Δημοτική' Log( '%@', s[1 .. s.length-2] ) // strip both first and last characters
return 0</lang>
Output:
2013-09-04 17:08:09.453 a.out[2257:507] night 2013-09-04 17:08:09.454 a.out[2257:507] sock 2013-09-04 17:08:09.454 a.out[2257:507] room 2013-09-04 17:08:09.455 a.out[2257:507] ημοτικ
Elena
ELENA 3.4 : <lang elena>import extensions.
public program [
var testString := "test". console printLine(testString Substring(1)). console printLine(testString Substring(0, testString length - 1)). console printLine(testString Substring(1, testString length - 2)).
]</lang>
- Output:
est tes es
Elixir
<lang elixir>iex(1)> str = "abcdefg" "abcdefg" iex(2)> String.slice(str, 1..-1) "bcdefg" iex(3)> String.slice(str, 0..-2) "abcdef" iex(4)> String.slice(str, 1..-2) "bcdef"</lang>
Emacs Lisp
<lang Emacs Lisp> (progn
(setq string "top and tail") (insert (format "%s\n" string) ) (setq len (length string) ) (insert (format "%s\n" (substring string 1) )) (insert (format "%s\n" (substring string 0 (1- len) ))) (insert (format "%s\n" (substring string 1 (1- len) ))))
</lang> Output:
top and tail op and tail top and tai op and tai
Erlang
<lang erlang>1> Str = "Hello". "Hello" 2> string:sub_string(Str, 2). % To strip the string from the right by 1 "ello" 3> string:sub_string(Str, 1, length(Str)-1). % To strip the string from the left by 1 "Hell" 4> string:sub_string(Str, 2, length(Str)-1). % To strip the string from both sides by 1 "ell"</lang>
Euphoria
<lang euphoria>function strip_first(sequence s)
return s[2..$]
end function
function strip_last(sequence s)
return s[1..$-1]
end function
function strip_both(sequence s)
return s[2..$-1]
end function
puts(1, strip_first("knight")) -- strip first character puts(1, strip_last("write")) -- strip last character puts(1, strip_both("brooms")) -- strip both first and last characters</lang>
F#
<lang fsharp>[<EntryPoint>] let main args =
let s = "一二三四五六七八九十" printfn "%A" (s.Substring(1)) printfn "%A" (s.Substring(0, s.Length - 1)) printfn "%A" (s.Substring(1, s.Length - 2)) 0</lang>
Output
"二三四五六七八九十" "一二三四五六七八九" "二三四五六七八九"
Factor
<lang factor>USING: io kernel sequences ; "Rosetta code" [ rest ] [ but-last ] [ rest but-last ] tri [ print ] tri@</lang>
- Output:
osetta code Rosetta cod osetta cod
Forth
In Forth, strings typically take up two cells on the stack, diagrammed ( c-addr u ), with C-ADDR the address of the string and U its length. Dropping leading and trailing characters then involves simple mathematical operations on the address or length, without mutating or copying the string.
<lang forth>: hello ( -- c-addr u )
s" Hello" ;
hello 1 /string type \ => ello
hello 1- type \ => hell
hello 1 /string 1- type \ => ell</lang>
This works for ASCII, and a slight variation (2 instead of 1 per character) will suffice for BIG5, GB2312, and like, but Unicode-general code can use +X/STRING and X\STRING- from Forth-200x's XCHAR wordset.
Fortran
<lang Fortran>program substring
character(len=5) :: string string = "Hello" write (*,*) string write (*,*) string(2:) write (*,*) string( :len(string)-1) write (*,*) string(2:len(string)-1)
end program substring</lang>
FreeBASIC
<lang freebasic>' FB 1.05.0 Win64
Dim s As String = "panda" Dim s1 As String = Mid(s, 2) Dim s2 As String = Left(s, Len(s) - 1) Dim s3 As String = Mid(s, 2, Len(s) - 2) Print s Print s1 Print s2 Print s3 Sleep</lang>
- Output:
panda anda pand and
Go
Go strings are byte arrays that can hold whatever you want them to hold. Common contents are ASCII and UTF-8. You use different techniques depending on how you are interpreting the string. The utf8 package functions shown here allows efficient extraction of first and last runes without decoding the entire string. <lang go>package main
import (
"fmt" "unicode/utf8"
)
func main() {
// ASCII contents: Interpreting "characters" as bytes. s := "ASCII" fmt.Println("String: ", s) fmt.Println("First byte removed: ", s[1:]) fmt.Println("Last byte removed: ", s[:len(s)-1]) fmt.Println("First and last removed:", s[1:len(s)-1]) // UTF-8 contents: "Characters" as runes (unicode code points) u := "Δημοτική" fmt.Println("String: ", u) _, sizeFirst := utf8.DecodeRuneInString(u) fmt.Println("First rune removed: ", u[sizeFirst:]) _, sizeLast := utf8.DecodeLastRuneInString(u) fmt.Println("Last rune removed: ", u[:len(u)-sizeLast]) fmt.Println("First and last removed:", u[sizeFirst:len(u)-sizeLast])
}</lang> Output:
String: ASCII First byte removed: SCII Last byte removed: ASCI First and last removed: SCI String: Δημοτική First rune removed: ημοτική Last rune removed: Δημοτικ First and last removed: ημοτικ
GW-BASIC
<lang qbasic>10 A$="knight":B$="socks":C$="brooms" 20 PRINT MID$(A$,2) 30 PRINT LEFT$(B$,LEN(B$)-1) 40 PRINT MID$(C$,2,LEN(C$)-2)</lang>
Groovy
Solution: <lang groovy>def top = { it.size() > 1 ? it[0..-2] : } def tail = { it.size() > 1 ? it[1..-1] : }</lang>
Test: <lang groovy>def testVal = 'upraisers' println """ original: ${testVal} top: ${top(testVal)} tail: ${tail(testVal)} top&tail: ${tail(top(testVal))} """</lang>
Output:
original: upraisers top: upraiser tail: praisers top&tail: praiser
Haskell
<lang Haskell>-- We define the functions to return an empty string if the argument is too -- short for the particular operation.
remFirst, remLast, remBoth :: String -> String
remFirst "" = "" remFirst cs = tail cs
remLast "" = "" remLast cs = init cs
remBoth (c:cs) = remLast cs remBoth _ = ""
main :: IO () main = do
let s = "Some string." mapM_ (\f -> putStrLn . f $ s) [remFirst, remLast, remBoth]</lang>
Alternative solution with builtin functions: <lang Haskell>word = "knights"
main = do
-- You can drop the first item -- using `tail` putStrLn (tail word)
-- The `init` function will drop -- the last item putStrLn (init word)
-- We can combine these two to drop -- the last and the first characters putStrLn (middle word)
-- You can combine functions using `.`, -- which is pronounced "compose" or "of" middle = init . tail</lang>
In short: <lang Haskell>main :: IO () main = mapM_ print $ [tail, init, init . tail] <*> ["knights"]</lang>
- Output:
"nights" "knight" "night"
Icon and Unicon
The task is accomplished by sub-stringing. <lang Icon>procedure main() write(s := "knight"," --> ", s[2:0]) # drop 1st char write(s := "sock"," --> ", s[1:-1]) # drop last write(s := "brooms"," --> ", s[2:-1]) # drop both end</lang>
It could also be accomplished (less clearly) by assigning into the string as below. Very awkward for both front and back. <lang Icon>write(s := "knight"," --> ", s[1] := "", s) # drop 1st char</lang>
J
The monadic primitives }.
(Behead) and }:
(Curtail) are useful for this task.
Example use:
<lang j> }. 'knight' NB. drop first item
night
}: 'socks' NB. drop last item
sock
}: }. 'brooms' NB. drop first and last items
room</lang>
Java
I solve this problem two ways. First I use substring which is relatively fast for small strings, since it simply grabs the characters within a set of given bounds. The second uses regular expressions, which have a higher overhead for such short strings.
<lang Java>public class RM_chars {
public static void main( String[] args ){ System.out.println( "knight".substring( 1 ) ); System.out.println( "socks".substring( 0, 4 ) ); System.out.println( "brooms".substring( 1, 5 ) ); // first, do this by selecting a specific substring // to exclude the first and last characters System.out.println( "knight".replaceAll( "^.", "" ) ); System.out.println( "socks".replaceAll( ".$", "" ) ); System.out.println( "brooms".replaceAll( "^.|.$", "" ) ); // then do this using a regular expressions }
}</lang>
Results:
night sock room night sock room
JavaScript
<lang javascript>alert("knight".slice(1)); // strip first character alert("socks".slice(0, -1)); // strip last character alert("brooms".slice(1, -1)); // strip both first and last characters</lang>
jq
jq uses 0-based indexing, so [1:] yields all but the first character, it being understood that data strings in jq are JSON strings. [0:-1], which can be abbreviated to [:-1], yields all but the last character, and so on. Here are some examples:<lang jq>"一二三四五六七八九十"[1:]' => "二三四五六七八九十"
"一二三四五六七八九十"[:-1]' => "一二三四五六七八九"
"一二三四五六七八九十"[1:-1]' => "二三四五六七八九"
"a"[1:-1] # => "" </lang> Recent versions of jq also have regular expression support, with named captures. This leads to many other possibilities, e.g.<lang jq>"abc" | capture( ".(?<monkey>.*)." ).monkey => "b"</lang>
Julia
<lang julia>julia> "My String"[2:end] # without first character "y String"
julia> "My String"[1:end-1] # without last character "My Strin"
julia> "My String"[2:end-1] # without first and last characters "y Strin"</lang>
K
K provides the system function _di
to delete an element at
a specified index. The following code is implemented using this feature.
<lang K>
s: "1234567890"
"1234567890"
s _di 0 /Delete 1st character
"234567890"
s _di -1+#s /Delete last character
"123456789"
(s _di -1+#s) _di 0 /String with both 1st and last character removed
"23456789" </lang> Another way to implement without using the above system function: <lang K>
s: "1234567890"
"1234567890"
1 _ s /Delete 1st character
"234567890"
-1 _ s /Delete last character
"123456789"
1 - -1 _ s /Delete 1st and last character
"23456789" </lang>
Kotlin
<lang scala>// version 1.0.6 fun main(args: Array<String>) {
val s = "Rosetta" println(s.drop(1)) println(s.dropLast(1)) println(s.drop(1).dropLast(1))
}</lang>
- Output:
osetta Rosett osett
Lasso
<lang Lasso>local(str = 'The quick grey rhino jumped over the lazy green fox.')
// String with first character removed string_remove(#str,-startposition=1,-endposition=1)
// String with last character removed string_remove(#str,-startposition=#str->size,-endposition=#str->size)
// String with both the first and last characters removed string_remove(string_remove(#str,-startposition=#str->size,-endposition=#str->size),-startposition=1,-endposition=1)</lang>
- Output:
he quick grey rhino jumped over the lazy green fox. The quick grey rhino jumped over the lazy green fox he quick grey rhino jumped over the lazy green fox
<lang Lasso>local(mystring = 'ÅÜÄÖカ')
- mystring -> remove(1,1)
- mystring
'
'
- mystring -> remove(#mystring -> size,1)
- mystring
'
'
- mystring -> remove(1,1)& -> remove(#mystring -> size,1)
- mystring</lang>
-> ÜÄÖカ
ÜÄÖ
Ä
Liberty BASIC
<lang lb>string$ = "Rosetta Code" Print Mid$(string$, 2) Print Left$(string$, (Len(string$) - 1)) Print Mid$(string$, 2, (Len(string$) - 2))</lang>
LiveCode
<lang LiveCode>put "pple" into x answer char 2 to len(x) of x // pple answer char 1 to -2 of x // ppl answer char 2 to -2 of x // ppl</lang>
Locomotive Basic
<lang locobasic>10 a$="knight":b$="socks":c$="brooms" 20 PRINT MID$(a$,2) 30 PRINT LEFT$(b$,LEN(b$)-1) 40 PRINT MID$(c$,2,LEN(c$)-2)</lang>
Lasso
<lang Lasso>local(str = 'The quick grey rhino jumped over the lazy green fox.')
// String with first character removed string_remove(#str,-startposition=1,-endposition=1) // > he quick grey rhino jumped over the lazy green fox.
// String with last character removed string_remove(#str,-startposition=#str->size,-endposition=#str->size) // > The quick grey rhino jumped over the lazy green fox
// String with both the first and last characters removed string_remove(string_remove(#str,-startposition=#str->size,-endposition=#str->size),-startposition=1,-endposition=1) // > he quick grey rhino jumped over the lazy green fox</lang>
Logo
<lang logo>make "s "|My string| print butfirst :s print butlast :s print butfirst butlast :s</lang>
Logtalk
Using atoms for representing strings: <lang logtalk>
- - object(top_and_tail).
:- public(test/1). test(String) :- sub_atom(String, 1, _, 0, MinusTop), write('String with first character cut: '), write(MinusTop), nl, sub_atom(String, 0, _, 1, MinusTail), write('String with last character cut: '), write(MinusTail), nl, sub_atom(String, 1, _, 1, MinusTopAndTail), write('String with first and last characters cut: '), write(MinusTopAndTail), nl.
- - end_object.
</lang> Sample output: <lang text> | ?- top_and_tail::test('Rosetta'). String with first character cut: osetta String with last character cut: Rosett String with first and last characters cut: osett yes </lang>
Lua
<lang lua>print (string.sub("knights",2)) -- remove the first character print (string.sub("knights",1,-2)) -- remove the last character print (string.sub("knights",2,-2)) -- remove the first and last characters</lang>
Maple
There are several ways to do this. The first is, I think, the simplest. <lang Maple>> s := "some string": > s[2..-1];
"ome string"
> s[1..-2];
"some strin"
> s[2..-2];
"ome strin"</lang>
The same functionality exists in the form of a procedure: <lang Maple>> substring( s, 2 .. -1 );
"ome string"
> substring( s, 1 .. -2 );
"some strin"
> substring( s, 2 .. -2 );
"ome strin"</lang>
Furthermore, there is a slightly different version in the "StringTools" package: <lang Maple>> use StringTools in > SubString( s, 2 .. -1 ); > SubString( s, 1 .. -1 ); > SubString( s, 2 .. -2 ) > end use;
"ome string"
"some string"
"ome strin"</lang>
(The difference between "substring" and "StringTools:-SubString" lies in how each treats a name as input; the former returns a name, while the latter returns a string.)
Mathematica
<lang Mathematica>StringDrop["input string",1] StringDrop["input string",-1] StringTake["input string",{2,-2}] </lang>
MATLAB / Octave
The following case will not handle UTF-8. However, Matlab supports conversion of utf-8 to utf-16 using native2unicode(). <lang MATLAB>
% String with first character removed
str(2:end)
% String with last character removed
str(1:end-1)
% String with both the first and last characters removed
str(2:end-1) </lang>
Nemerle
<lang Nemerle>using System; using System.Console;
module RemoveChars {
Main() : void { def str = "*A string*"; def end = str.Remove(str.Length - 1); // from pos to end def beg = str.Remove(0, 1); // start pos, # of chars to remove def both = str.Trim(array['*']); // with Trim() you need to know what char's you're removing WriteLine($"$str -> $beg -> $end -> $both"); }
}</lang>
NetRexx
<lang netrexx>/**********************************************************************
- 02.08.2013 Walter Pachl translated from REXX
- /
z = 'abcdefghijk' l=z.length() say ' the original string =' z If l>=1 Then Do
Say 'string first character removed =' z.substr(2) say 'string last character removed =' z.left(l-1) End
If l>=2 Then
Say 'string first & last character removed =' z.substr(2,l-2)</lang>
NewLISP
<lang NewLISP>(let (str "rosetta")
;; strip first char (println (1 str)) ;; strip last char (println (0 -1 str)) ;; strip both first and last characters (println (1 -1 str)))</lang>
Nim
<lang nim>var s = "The quick μ brown fox" echo(s.substr(1)) echo(s.substr(0,s.len-2)) echo(s.substr(1,s.len-2))
- using slices
echo(s[1 .. -2])</lang>
- Output:
he quick μ brown fox The quick μ brown fo he quick μ brown fo he quick μ brown fo
Objeck
<lang objeck> bundle Default {
class TopTail { function : Main(args : System.String[]) ~ Nil { string := "test"; string->SubString(1, string->Size() - 1)->PrintLine(); string->SubString(string->Size() - 1)->PrintLine(); string->SubString(1, string->Size() - 2)->PrintLine(); } }
} </lang>
OCaml
<lang ocaml>let strip_first_char str =
if str = "" then "" else String.sub str 1 ((String.length str) - 1)
let strip_last_char str =
if str = "" then "" else String.sub str 0 ((String.length str) - 1)
let strip_both_chars str =
match String.length str with | 0 | 1 | 2 -> "" | len -> String.sub str 1 (len - 2)
let () =
print_endline (strip_first_char "knight"); print_endline (strip_last_char "socks"); print_endline (strip_both_chars "brooms");
- </lang>
Oforth
<lang Oforth>: topAndTail(s)
s right(s size 1-) println s left(s size 1-) println s extract(2, s size 1- ) println ;</lang>
- Output:
topAndTail("MyString") yString MyStrin yStrin
PARI/GP
<lang parigp>df(s)=concat(vecextract(Vec(s),1<<#s-2)); dl(s)=concat(vecextract(Vec(s),1<<(#s-1)-1)); db(s)=concat(vecextract(Vec(s),1<<(#s-1)-2));</lang>
Pascal
See Delphi
Perl
<lang perl>print substr("knight",1), "\n"; # strip first character print substr("socks", 0, -1), "\n"; # strip last character print substr("brooms", 1, -1), "\n"; # strip both first and last characters</lang>
In perl, we can also remove the last character from a string variable with the chop function:
<lang perl>$string = 'ouch'; $bits = chop($string); # The last letter is returned by the chop function print $bits; # h print $string; # ouc # See we really did chop the last letter off</lang>
Perl 6
Perl 6 provides both functional and method forms of substr. Note that, unlike in Perl 5, offsets from the end do not use negative numbers, but instead require a function expressing the negative offset relative to the length parameter, which is supplied by the operator. The form *-1 is just a simple way to write such a function.
We use musical sharps and flats to illustrate that Perl is comfortable with characters from any Unicode plane.
<lang perl6>my $s = '𝄪♯♮♭𝄫';
print qq:to/END/;
Original: $s
Remove first character: { substr($s, 1) } { $s.substr(1) }
Remove last character: { substr($s, 0, *-1) } { $s.substr( 0, *-1) } { $s.chop }
Remove first and last characters: { substr($s, 1, *-1) } { $s.substr(1, *-1) } END</lang>
- Output:
Original: 𝄪♯♮♭𝄫 Remove first character: ♯♮♭𝄫 ♯♮♭𝄫 Remove last character: 𝄪♯♮♭ 𝄪♯♮♭ 𝄪♯♮♭ Remove first and last characters: ♯♮♭ ♯♮♭
Phix
<lang Phix>constant s = "(test)" ?s[2..-1] ?s[1..-2] ?s[2..-2]</lang>
- Output:
"test)" "(test" "test"
PHP
<lang php><?php echo substr("knight", 1), "\n"; // strip first character echo substr("socks", 0, -1), "\n"; // strip last character echo substr("brooms", 1, -1), "\n"; // strip both first and last characters ?></lang>
PicoLisp
<lang PicoLisp>: (pack (cdr (chop "knight"))) # Remove first character -> "night"
- (pack (head -1 (chop "socks"))) # Remove last character
-> "sock"
- (pack (cddr (rot (chop "brooms")))) # Remove first and last characters
-> "room"</lang>
PL/I
<lang PL/I> declare s character (100) varying; s = 'now is the time to come to the aid of the party'; if length(s) <= 2 then stop; put skip list ('First character removed=' || substr(s,2) ); put skip list ('Last character removed=' || substr(s, 1, length(s)-1) ); put skip list ('One character from each end removed=' ||
substr(s, 2, length(s)-2) );
</lang> OUTPUT:
First character removed=ow is the time to come to the aid of the party Last character removed=now is the time to come to the aid of the part One character from each end removed=ow is the time to come to the aid of the part
PowerShell
First method
<lang PowerShell> $string = "top and tail" $string $string.Substring(1) $string.Substring(0, $string.Length - 1) $string.Substring(1, $string.Length - 2) </lang>
Second method
<lang PowerShell> $string = "top and tail" $string $string[1..($string.Length - 1)] -join "" $string[0..($string.Length - 2)] -join "" $string[1..($string.Length - 2)] -join "" </lang> Output:
top and tail op and tail top and tai op and tai
Prolog
Works with SWI-Prolog.
<lang Prolog>remove_first_last_chars :- L = "Rosetta", L = [_|L1], remove_last(L, L2), remove_last(L1, L3), writef('Original string : %s\n', [L]), writef('Without first char : %s\n', [L1]), writef('Without last char : %s\n', [L2]), writef('Without first/last chars : %s\n', [L3]).
remove_last(L, LR) :- append(LR, [_], L).</lang> Output :
?- remove_first_last_chars. Original string : Rosetta Without first char : osetta Without last char : Rosett Without first/last chars : osett true.
PureBasic
<lang PureBasic>If OpenConsole()
PrintN(Right("knight", Len("knight") - 1)) ;strip the first letter PrintN(Left("socks", Len("socks")- 1)) ;strip the last letter PrintN(Mid("brooms", 2, Len("brooms") - 2)) ;strip both the first and last letter Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input() CloseConsole()
EndIf</lang> Sample output:
night sock room
Python
<lang python>print "knight"[1:] # strip first character print "socks"[:-1] # strip last character print "brooms"[1:-1] # strip both first and last characters</lang>
Racket
<lang racket>
- lang racket
(define str "ストリング")
(substring str 1) (substring str 0 (sub1 (string-length str))) (substring str 1 (sub1 (string-length str))) </lang>
Output:
"トリング" "ストリン" "トリン"
Raven
<lang Raven>define println use $s
$s print "\n" print
"0123456789" as $str
define offTheTop use $s
$s 1 0x7FFFFFFF extract
define offTheTail use $s
$s 0 -1 extract
$str offTheTop println
$str offTheTail println
$str offTheTop offTheTail println</lang>
- Output:
123456789 012345678 12345678
REXX
error prone
This REXX version is error prone in that if the string is less than two characters, then the left and/or substr BIFs will fail (because of an invalid length specified). <lang rexx>/*REXX program demonstrates removal of 1st/last/1st-and-last characters from a string.*/ @ = 'abcdefghijk' say ' the original string =' @ say 'string first character removed =' substr(@, 2) say 'string last character removed =' left(@, length(@) -1) say 'string first & last character removed =' substr(@, 2, length(@) -2)
/*stick a fork in it, we're all done. */ /* ╔═══════════════════════════════════════════════════════════════════════════════╗ ║ However, the original string may be null or exactly one byte in length which ║ ║ will cause the BIFs to fail because of either zero or a negative length. ║ ╚═══════════════════════════════════════════════════════════════════════════════╝ */</lang>
output
the original string = abcdefghijk string first character removed = bcdefghijk string last character removed = abcdefghij string first & last character removed = bcdefghij
robust version
This REXX version correctly handles a string of zero (null) or one byte. <lang rexx>/*REXX program demonstrates removal of 1st/last/1st-and-last characters from a string.*/ @ = 'abcdefghijk' say ' the original string =' @ say 'string first character removed =' substr(@, 2) say 'string last character removed =' left(@, max(0, length(@) -1)) say 'string first & last character removed =' substr(@, 2, max(0, length(@) -2)) exit /*stick a fork in it, we're all done. */
/* [↓] an easier to read version using a length variable.*/
@ = 'abcdefghijk' L=length(@) say ' the original string =' @ say 'string first character removed =' substr(@, 2) say 'string last character removed =' left(@, max(0, L-1) ) say 'string first & last character removed =' substr(@, 2, max(0, L-2) )</lang> output is the same as the 1st REXX version.
faster version
This REXX version is faster (uses parse instead of multiple BIFs). <lang rexx>/*REXX program demonstrates removal of 1st/last/1st-and-last characters from a string.*/ @ = 'abcdefghijk' say ' the original string =' @
parse var @ 2 z say 'string first character removed =' z
m=length(@) - 1 parse var @ z +(m) say 'string last character removed =' z
n=length(@) - 2
parse var @ 2 z +(n)
if n==0 then z= /*handle special case of a length of 2.*/
say 'string first & last character removed =' z /*stick a fork in it, we're all done. */</lang>
output is the same as the 1st REXX version.
Ring
<lang ring> aString = "1Welcome to the Ring Programming Language2" see substr(aString,2,len(aString)-1) + nl + substr(aString,1,len(aString)-1) + nl + substr(aString,2,len(aString)-2) + nl </lang>
Ruby
<lang ruby>puts "knight"[1..-1] # strip first character puts "socks"[0..-2] # strip last character puts "socks".chop # alternate way to strip last character puts "brooms"[1..-2] # strip both first and last characters puts "与今令"[1..-2] # => 今</lang>
Run BASIC
<lang runbasic>s$ = "Run BASIC" print mid$(s$,2) 'strip first print left$(s$,len(s$) -1) 'strip last print mid$(s$,2,len(s$) -2) 'strip first and last</lang>
Scala
<lang scala>println("knight".tail) // strip first character println("socks".init) // strip last character println("brooms".tail.init) // strip both first and last characters</lang>
Seed7
<lang seed7>$ include "seed7_05.s7i";
const proc: main is func
local const string: stri is "upraisers"; begin writeln("Full string: " <& stri); writeln("Without first: " <& stri[2 ..]); writeln("Without last: " <& stri[.. pred(length(stri))]); writeln("Without both: " <& stri[2 .. pred(length(stri))]); end func;</lang>
Output:
Full string: upraisers Without first: praisers Without last: upraiser Without both: praiser
Sidef
Strip any characters: <lang ruby>say "knight".substr(1); # strip first character say "socks".substr(0, -1); # strip last character say "brooms".substr(1, -1); # strip both first and last characters say "与今令".substr(1, -1); # => 今</lang>
- Output:
night sock room 今
Strip graphemes: <lang ruby>var gstr = "J\x{332}o\x{332}s\x{332}e\x{301}\x{332}"; say gstr-/^\X/; # strip first grapheme say gstr-/\X\z/; # strip last grapheme say gstr.sub(/^\X/).sub(/\X\z/); # strip both first and last graphemes</lang>
- Output:
o̲s̲é̲ J̲o̲s̲ o̲s̲
Smalltalk
These all use built-in collection methods that will work with any kind of ordered collection, not just Strings. There is no error checking. They will fail if the string is not at least two characters long. <lang smalltalk> s := 'upraisers'. Transcript show: 'Top: ', s allButLast; nl. Transcript show: 'Tail: ', s allButFirst; nl. Transcript show: 'Without both: ', s allButFirst allButLast; nl. Transcript show: 'Without both using substring method: ', (s copyFrom: 2 to: s size - 1); nl. </lang>
- Output:
Top: upraiser Tail: praisers Without both: praiser Without both using substring method: praiser
SNOBOL4
<lang snobol4> "knight" len(1) rem . output ;* strip first character
"socks" rtab(1) . output ;* strip last character "brooms" len(1) rtab(1) . output ;* strip both first and last characters</lang>
Standard ML
<lang sml>- val str = "abcde"; val str = "abcde" : string - String.substring(str, 1, String.size str - 1); val it = "bcde" : string - String.substring(str, 0, String.size str - 1); val it = "abcd" : string - String.substring(str, 1, String.size str - 2); val it = "bcd" : string</lang>
Swift
Swift strings are native Unicode strings and do not index through the code points. Swift's String.Index
refers to true Unicode characters (Unicode grapheme clusters). Swift standard library has generic functionality that not only works with strings, but also with any type that conforms to relevant protocols. The first method presented here uses generic functions from Swift standard library:
<lang swift>let txt = "0123456789" println(dropFirst(txt)) println(dropLast(txt)) println(dropFirst(dropLast(txt)))</lang>
- Output:
123456789 012345678 12345678
The other method is slicing by range subscripting: <lang swift>let txt = "0123456789" println(txt[txt.startIndex.successor() ..< txt.endIndex]) println(txt[txt.startIndex ..< txt.endIndex.predecessor()]) println(txt[txt.startIndex.successor() ..< txt.endIndex.predecessor()])</lang>
- Output:
123456789 012345678 12345678
Another way is mutating the string: <lang swift>var txt = "0123456789" txt.removeAtIndex(txt.startIndex) txt.removeAtIndex(txt.endIndex.predecessor())</lang> The above functions return what they remove. You can also extend String type and define BASIC-style functions: <lang swift>extension String {
/// Ensure positive indexes private func positive(index: Int) -> Int { if index >= 0 { return index } return count(self) + index } /// Unicode character by zero-based integer (character) `index` /// Supports negative character index to count from end. (-1 returns character before last) subscript(index: Int) -> Character { return self[advance(startIndex, positive(index))] } /// String slice by character index subscript(range: Range<Int>) -> String { return self[advance(startIndex, range.startIndex) ..< advance(startIndex, range.endIndex, endIndex)] } /// Left portion of text to `index` func left(index : Int) -> String { return self[0 ..< positive(index)] } /// Right portion of text from `index` func right(index : Int) -> String{ return self[positive(index) ..< count(self)] } /// From `start` index until `end` index func mid(start: Int, _ end: Int) -> String { return self[positive(start) ..< positive(end)] }
}
let txt = "0123456789"
txt.right(1) // Right part without first character txt.left(-1) // Left part without last character txt.mid(1,-1) // Middle part without first and last character</lang>
Tcl
<lang tcl>puts [string range "knight" 1 end]; # strip first character puts [string range "write" 0 end-1]; # strip last character puts [string range "brooms" 1 end-1]; # strip both first and last characters</lang>
TorqueScript
String with first character removed
%string = "Moo"; %string = getSubStr(%string, 1, strLen(%string) - 1); echo(%string);
String with last character removed
%string = "Moo"; %string = getSubStr(%string, 0, strLen(%string) - 1); echo(%string);
String with both the first and last characters removed
%string = "Moo"; %string = getSubStr(%string, 1, strLen(%string) - 2); echo(%string);
Output:
oo Mo o
TUSCRIPT
<lang tuscript> $$ MODE TUSCRIPT str="upraisers" str1=EXTRACT (str,2,0) str2=EXTRACT (str,0,-1) str3=EXTRACT (str,2,-1) PRINT str PRINT str1 PRINT str2 PRINT str3 </lang> Output:
upraisers praisers upraiser upraiser
UNIX Shell
First or last character:
<lang bash>str='abcdefg' echo "${str#?}" # Remove first char echo "${str%?}" # Remove last char</lang>
First and last character:
- Only zsh supports nested string manipulation.
- <lang bash>echo ${${str#?}%?} # Remove first & last chars</lang>
- bash and ksh, use substring expansion, from character index 1 for length of (string length) minus 2
- <lang bash>echo "${s:1:${#s}-2}"</lang>
- POSIX shells like dash, need a temp variable
- <lang bash>tmp=${s#?}; tmp=${tmp%?}; echo "$tmp"</lang>
Vala
<lang vala> // declare test string string s = "Hello, world!"; // remove first letter string s_first = s[1:s.length]; //remove last letter string s_last = s[0:s.length - 1]; // remove first and last letters string s_first_last = s[1:s.length - 1]; </lang>
VBScript
<lang VBScript>Function TopNTail(s,mode) Select Case mode Case "top" TopNTail = Mid(s,2,Len(s)-1) Case "tail" TopNTail = Mid(s,1,Len(s)-1) Case "both" TopNTail = Mid(s,2,Len(s)-2) End Select End Function
WScript.Echo "Top: UPRAISERS = " & TopNTail("UPRAISERS","top") WScript.Echo "Tail: UPRAISERS = " & TopNTail("UPRAISERS","tail") WScript.Echo "Both: UPRAISERS = " & TopNTail("UPRAISERS","both")</lang>
- Output:
Top: UPRAISERS = PRAISERS Tail: UPRAISERS = UPRAISER Both: UPRAISERS = PRAISER
XPL0
<lang XPL0>include c:\cxpl\stdlib; char S, P; [S:= "Smiles"; Text(0, S+1); \first character removed CrLf(0); P:= S + StrLen(S) - 2; \point to last character in string P(0):= P(0) ! $80; \set the MSb on the last character Text(0, S); \last character removed CrLf(0); Text(0, S+1); \first and last characters removed CrLf(0); ]</lang>
Output:
miles Smile mile
zkl
<lang zkl>"Smiles"[1,*] //-->miles "Smiles"[0,-1] //-->Smile "Smiles"[1,-1] //-->mile</lang> [] format is [offset (zero based), length]. * means "to the end", a negative number means from the end.
ZX Spectrum Basic
<lang zxbasic>10 PRINT FN f$("knight"): REM strip the first letter. You can also write PRINT "knight"(2 TO) 20 PRINT FN l$("socks"): REM strip the last letter 30 PRINT FN b$("brooms"): REM strip both the first and last letter 100 STOP
9000 DEF FN f$(a$)=a$(2 TO LEN(a$)) 9010 DEF FN l$(a$)=a$(1 TO LEN(a$)-(1 AND (LEN(a$)>=1))) 9020 DEF FN b$(a$)=FN l$(FN f$(a$)) </lang>
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