JavaScript chop slice trim off last character in string

Question

I have a string  12345 00  and I would like it to return 12345 0   I have looked at trim  but it looks like it is only trimming whitespace and slice which I don t see how this would work  Any suggestions

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Use substring to get everything to the left of  bar  But first you have to get the instr of  bar in the string   str substring 3  7     3 is that start and 7 is the length

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The easiest method is to use the slice method of the string  which allows negative positions  corresponding to offsets from the end of the string    const s    your string   const withoutLastFourChars   s slice 0  -4     If you needed something more general to remove everything after  and including  the last underscore  you could do the following  so long as s is guaranteed to contain at least one underscore     x000D   x000D  const s    your string   x000D  const withoutLastChunk   s slice 0  s lastIndexOf        x000D  console log withoutLastChunk   x000D   x000D   x000D

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Performance Today 2020 05 13 I perform tests of chosen solutions on Chrome v81 0  Safari v13 1 and Firefox v76 0 on MacOs High Sierra v10 13 6  Conclusions  the slice 0 -1  D  is fast or fastest solution for short and long strings and it is recommended as fast cross-browser solution solutions based on substring  C  and substr E  are fast solutions based on regular expressions  A B  are slow medium fast solutions B  F and G are slow for long strings solution F is slowest for short strings  G is slowest for long strings   Details I perform two tests for solutions A  B  C  D  E ext   F  G my   for 8-char short string  from OP question  - you can run it HERE for 1M long string - you can run it HERE  Solutions are presented in below snippet  x000D   x000D  function A str      return str replace               function B str      return str match           1      function C str      return str substring 0  str length - 1      function D str      return str slice 0  -1       function E str      return str substr 0  str length - 1      function F str      let s  str split        s pop      return s join         function G str      let s       for let i 0  i lt str length-1  i    s  str i     return s           ---------    TEST    ---------  let log    f   gt console log    f name     f  12345 00         A B C D E F G  map f  gt log f    x000D  This snippet only presents soutions x000D   x000D   x000D   Here are example results for Chrome for short string

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You can  in fact  remove the last arr length - 2 items of an array using arr length   2  which if the array length was 5  would remove the last 3 items  Sadly  this does not work for strings  but we can use split   to split the string  and then join   to join the string after we ve made any modifications   x000D   x000D  var str    string   String prototype removeLast   function n      var string   this split       string length   string length - n    return string join        console log str removeLast 3   x000D   x000D   x000D

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The shortest way   str slice 0  -1

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Try this    x000D   x000D  const myString    Hello World    x000D  console log myString slice 0  -1    x000D   x000D   x000D

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debris   string split        explode string into array of strings indexed by      debris pop      pop last element off the array  which you didn t want   result   debris join         fuse the remainng items together like the sun

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Use regex    x000D   x000D  let aStr    12345 00   x000D  aStr   aStr replace            x000D  console log aStr   x000D   x000D   x000D

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You can use the substring function    x000D   x000D  let str    12345 00   x000D  str   str substring 0  str length - 1   x000D  console log str   x000D   x000D   x000D    This is the accepted answer  but as per the conversations below  the slice syntax is much clearer    x000D   x000D  let str    12345 00   x000D  str   str slice 0  -1    x000D  console log str   x000D   x000D   x000D

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For a number like your example  I would recommend doing this over substring    x000D   x000D  console log parseFloat  12345 00   toFixed 1    x000D   x000D   x000D    Do note that this will actually round the number  though  which I would imagine is desired but maybe not    x000D   x000D  console log parseFloat  12345 46   toFixed 1    x000D   x000D   x000D

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Try this    lt script gt      var x  foo foo foo bar       for  var i 0  i lt  x length  i              if  x i        amp  amp  x i 1    b                 break                    else               document write x i                     lt  script gt    You can also try the live working example on http   jsfiddle net informativejavascript F7WTn 87

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captures any character multiple times    x000D   x000D  console log  a string  match           1    x000D   x000D   x000D        matches last character  in this case    x000D   x000D  console log  a string  match             x000D   x000D   x000D        matches the end of the string    x000D   x000D  console log  a string  match        2     1    x000D   x000D   x000D

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If you want to do generic rounding of floats  instead of just trimming the last character   var float1   12345 00      float2   12345 4567      float3   12345 982   var MoreMath                    Rounds a value to the specified number of decimals         param float value The value to be rounded         param int nrDecimals The number of decimals to round value to         return float value rounded to nrDecimals decimals             round  function  value  nrDecimals            var x   nrDecimals  gt  0   10   parseInt nrDecimals  10    1          return Math round value   x    x           MoreMath round float1  1    gt  12345 0 MoreMath round float2  1    gt  12345 5 MoreMath round float3  1    gt  12346 0   EDIT  Seems like there exists a built in function for this  as Paolo points out  That solution is obviously much cleaner than mine  Use parseFloat followed by toFixed

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You can use slice  You just have to make sure you know how to use it  Positive  s are relative to the beginning  negative numbers are relative to the end   js gt  12345 00  slice 0 -1  12345 0

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x000D   x000D  const str    test    x000D  console log str slice 0  -1    x000D   x000D   x000D

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A regular expression is what you are looking for    x000D   x000D  let str    foo bar   x000D  console log str replace   bar          x000D   x000D   x000D

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Jason S       You can use slice  You just have to   make sure you know how to use it    Positive  s are relative to the   beginning  negative numbers are   relative to the end       js  12345 00  slice 0 -1    12345 0   Sorry for my graphomany but post was tagged  jquery  earlier  So  you can t use slice   inside jQuery because slice   is jQuery method for operations with DOM elements  not substrings      In other words answer  Jon Erickson suggest really perfect solution   However  your method will works out of jQuery function  inside simple Javascript  Need to say due to last discussion in comments  that jQuery is very much more often renewable extension of JS than his own parent most known ECMAScript   Here also exist two methods   as our   string substring from to  as plus if  to  index nulled returns the rest of string  so  string substring from  positive or negative      and some other - substr   - which provide range of substring and  length  can be positive only  string substr start length   Also some maintainers suggest that last method string substr start length  do not works or work with error for MSIE

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Be aware that String prototype   split  slice  substr  substring   operate on UTF-16 encoded strings None of the previous answers are Unicode-aware  Strings are encoded as UTF-16 in most modern JavaScript engines  but higher Unicode code points require surrogate pairs  so older  pre-existing string methods operate on UTF-16 code units  not Unicode code points   x000D   x000D  const string         console log string slice 0  -1          ud83e  console log string substr 0  string length - 1          ud83e  console log string substring 0  string length - 1          ud83e  console log string replace                   ud83e  console log string match           1          ud83e   const utf16Chars   string split       utf16Chars pop    console log utf16Chars join             ud83e  x000D   x000D   x000D   In addition  RegExp methods  as suggested in older answers  don   t match line breaks at the end   x000D   x000D  const string    Hello  world  n    console log string replace           endsWith   n        true console log string match               null      true x000D   x000D   x000D    Use the string iterator to iterate characters Unicode-aware code utilizes the string   s iterator  see Array from and     spread  string Symbol iterator  can be used  e g  instead of string  as well  Also see How to split Unicode string to characters in JavaScript  Examples   x000D   x000D  const string         console log Array from string  slice 0  -1  join              console log        string   slice 0  -1  join              x000D   x000D   x000D   Use the s and u flags on a RegExp The dotAll or s flag makes   match line break characters  the unicode or u flag enables certain Unicode-related features  Note that  when using the u flag  you eliminate unnecessary identity escapes  as these are invalid in a u regex  e g     is fine  as it would start a character class without the backslash  but    isn   t  as it   s a   with or without the backslash  so you need to remove the backslash  Examples   x000D   x000D  const unicodeString          lineBreakString    Hello  world  n    console log lineBreakString replace     s      endsWith   n        false console log lineBreakString match         s      null      false console log unicodeString replace     su             console log unicodeString match         su  1             Now  split  can be made Unicode-aware   const unicodeCharacterArray   unicodeString split       su     lineBreakCharacterArray   lineBreakString split       su    unicodeCharacterArray pop    lineBreakCharacterArray pop    console log unicodeCharacterArray join              console log lineBreakCharacterArray join     endsWith   n        false x000D   x000D   x000D    Note that some graphemes consist of more than one code point  e g     which consists of the sequence   U 1F3F3   VS16  U FE0F   ZWJ  U 200D     U 1F308   Here  even Array from will split this into four    characters     Matching those is possible with the Unicode property escapes sequence properties proposal

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Using JavaScript s slice function    x000D   x000D  let string    foo bar   x000D  string   string slice 0  -4      Slice off last four characters here x000D  console log string   x000D   x000D   x000D    This could be used to remove   bar  at end of a string  of any length

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Via slice indexStart  indexEnd  method - note  this does NOT CHANGE the existing string  it creates a copy and changes the copy  console clear    let str    quot 12345 00 quot   let a   str slice 0  str length -1  console log a   quot  lt   a quot    console log str   quot  lt   str is NOT changed quot     Via Regular Expression method - note  this does NOT CHANGE the existing string  it creates a copy and changes the copy  console clear    let regExp       g let b   str replace regExp  quot  quot   console log b   quot  lt   b quot    console log str   quot  lt   str is NOT changed quot     Via array splice   method - gt  this only works on arrays  and it CHANGES  the existing array  so careful with this one   you ll need to convert a string to an array first  then back  console clear    let str    quot 12345 00 quot   let strToArray   str split  quot  quot   console log strToArray   quot  lt   strToArray quot    let spliceMethod   strToArray splice str length-1  1  str   strToArray join  quot  quot   console log str   quot  lt   str is changed now quot

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In cases where you want to remove something that is close to the end of a string  in case of variable sized strings  you can combine slice   and substr     I had a string with markup  dynamically built  with a list of anchor tags separated by comma  The string was something like   var str     lt a gt text 1  lt  a gt  lt a gt text 2  lt  a gt  lt a gt text 2 3  lt  a gt  lt a gt text abc  lt  a gt      To remove the last comma I did the following   str   str slice 0  -5    str substr -4

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https   stackoverflow com questions 34817546 javascript-how-to-delete-last-two-characters-in-a-string  Just use trim if you don t want spaces   quot 11 01   C quot  slice 0 -2  trim

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You can use the substring method of JavaScript string objects   s   s substring 0  s length - 4    It unconditionally removes the last four characters from string s   However  if you want to conditionally remove the last four characters  only if they are exactly  bar   var re     bar    s replace re

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Here is an alternative that i don t think i ve seen in the other answers  just for fun    x000D   x000D  var strArr    hello i m a string  split      x000D  strArr pop    x000D  document write strArr join       x000D   x000D   x000D    Not as legible or simple as slice or substring but does allow you to play with the string using some nice array methods  so worth knowing

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if str substring str length - 4       bar         str   str substring 0  str length - 4

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How about    x000D   x000D  let myString    12345 00   x000D  console log myString substring 0  myString length - 1    x000D   x000D   x000D

[javascript] JavaScript chop/slice/trim off last character in string

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