How can I split a string into segments of n characters

Question

As the title says  I ve got a string and I want to split into segments of n characters   For example   var str    abcdefghijkl     after some magic with n 3  it will become  var arr     abc   def   ghi   jkl      Is there a way to do this

User · Answer

Some clean solution without using regular expressions:

/**
* Create array with maximum chunk length = maxPartSize
* It work safe also for shorter strings than part size
**/
function convertStringToArray(str, maxPartSize){

  const chunkArr = [];
  let leftStr = str;
  do {

    chunkArr.push(leftStr.substring(0, maxPartSize));
    leftStr = leftStr.substring(maxPartSize, leftStr.length);

  } while (leftStr.length > 0);

  return chunkArr;
};

Usage example - https://jsfiddle.net/maciejsikora/b6xppj4q/.

I also tried to compare my solution to regexp one which was chosen as right answer. Some test can be found on jsfiddle - https://jsfiddle.net/maciejsikora/2envahrk/. Tests are showing that both methods have similar performance, maybe on first look regexp solution is little bit faster, but judge it Yourself.

User · Answer

str match    3  g        gt    abc    def    ghi    jkl

User · Answer

x000D   x000D  var str    abcdefghijkl   x000D  console log str match    1 3  g    x000D   x000D   x000D    Note  Use  1 3  instead of just  3  to include the remainder for string lengths that aren t a multiple of 3  e g    x000D   x000D  console log  abcd  match    1 3  g         abc    d   x000D   x000D   x000D      A couple more subtleties    If your string may contain newlines  which you want to count as a character rather than splitting the string   then the   won t capture those  Use    s S  1 3   instead   Thanks  Mike   If your string is empty  then match   will return null when you may be expecting an empty array  Protect against this by appending          So you may end up with    x000D   x000D  var str    abcdef  t r nghijkl   x000D  var parts   str match    s S  1 3  g         x000D  console log parts   x000D   x000D  console log    match    s S  1 3  g          x000D   x000D   x000D

User · Answer

Coming a little later to the discussion but here a variation that s a little faster than  the substring   array push one      substring   array push   end precalc var chunks        for  var i   0  e   3  charsLength   str length  i  lt  charsLength  i    3  e    3        chunks push str substring i  e        Pre-calculating the end value as part of the for loop is faster than doing the inline math inside substring  I ve tested it in both Firefox and Chrome and they both show speedup   You can try it here

User · Answer

With  split   var arr   str split      lt        3                    abc    def    ghi    jkl      and  replace will be   var replaced   str replace      lt      3          g                abc    def    ghi    jkl             is to to stop before end     without is   var arr        str split      lt        3                     abc    def    ghi    jkl           I don t know why is not    abc    def    ghi    jkl          comment  var replaced   str replace      lt      3     g               abc    def    ghi    jkl        ignoring group           is no need in  replace but in  split is adding groups to arr   var arr   str split      lt      3                    abc    abc    def    abc    ghi    abc    jkl

User · Answer

function chunk er   return er match    1 75  g  join   n        Above function is what I use for Base64 chunking  It will create a line break ever 75 characters

User · Answer

My solution  ES6 syntax    const source    8d7f66a9273fc766cd66d1d   const target       for       const array   Array from source       array length      target push array splice 0 2  join      2      We could even create a function with this   function splitStringBySegmentLength source  segmentLength        if   segmentLength    segmentLength  lt  1  throw Error  Segment length must be defined and greater than equal to 1        const target           for           const array   Array from source           array length          target push array splice 0 segmentLength  join            return target      Then you can call the function easily in a reusable manner   const source    8d7f66a9273fc766cd66d1d   const target   splitStringBySegmentLength source  2     Cheers

User · Answer

Building on the previous answers to this question  the following function will split a string  str  n-number  size  of characters   function chunk str  size        return str match new RegExp    1     size         g         Demo   x000D   x000D   function     x000D    function chunk str  size    x000D      return str match new RegExp    1     size         g     x000D      x000D     x000D    var str    HELLO WORLD   x000D    println  Simple binary representation     x000D    println chunk textToBin str   8  join   n     x000D    println   nNow for something crazy     x000D    println chunk textToHex str  4   8  map function h    return  0x    h    join         x000D     x000D       Utiliy functions  you can ignore these  x000D    function textToBin text    return textToBase text  2  8     x000D    function textToHex t  w    return pad textToBase t 16 2   roundUp t length  w  2   00      x000D    function pad val  len  chr    return  repeat chr  len    val  slice -len     x000D    function print text    document getElementById  out   innerHTML     text           x000D    function println text    print  text            n      x000D    function repeat chr  n    return new Array n   1  join chr     x000D    function textToBase text  radix  n    x000D      return text split     reduce function result  chr    x000D        return result   pad chr charCodeAt 0  toString radix   n   0    x000D              x000D      x000D    function roundUp numToRound  multiple     x000D      if  multiple     0  return numToRound  x000D      var remainder   numToRound   multiple  x000D      return remainder     0   numToRound   numToRound   multiple - remainder  x000D      x000D        x000D   out   x000D    white-space  pre  x000D    font-size  0 8em  x000D    x000D   lt div id  out  gt  lt  div gt  x000D   x000D   x000D

User · Answer

Here we intersperse a string with another string every n characters   export const intersperseString    n  number  intersperseWith  string  str  string   string   gt       let ret   str slice 0 n   remaining   str     while  remaining        let v   remaining slice 0  n       remaining   remaining slice v length       ret    intersperseWith   v         return ret        if we use the above like so   console log splitString 3       aagaegeage       we get      aag aag aeg eag e   and here we do the same  but push to an array   export const sperseString    n  number  str  string   Array lt string gt    gt       let ret       remaining   str     while  remaining        let v   remaining slice 0  n       remaining   remaining slice v length       ret push v          return ret        and then run it   console log sperseString 5   foobarbaztruck       we get         fooba    rbazt    ruck      if someone knows of a way to simplify the above code  lmk  but it should work fine for strings

User · Answer

If you didn t want to use a regular expression     var chunks        for  var i   0  charsLength   str length  i  lt  charsLength  i    3        chunks push str substring i  i   3        jsFiddle      otherwise the regex solution is pretty good

User · Answer

const chunkStr    str  n  acc    gt             if  str length     0            return acc       else           acc push str substring 0  n            return chunkStr str substring n   n  acc           const str    abcdefghijkl   const splittedString   chunkStr str  3         Clean solution without REGEX

User · Answer

Here s a way to do it without regular expressions or explicit loops  although it s stretching the definition of a one liner a bit   const input    abcdefghijlkm       Change  3  to the desired split length  const output   input split     reduce  s  c    gt   let l   s length-1   s l   amp  amp  s l  length  lt  3    s l     c   s push c   return s          console log output       output     abc    def    ghi    jlk    m      It works by splitting the string into an array of individual characters  then using Array reduce to iterate over each character   Normally reduce would return a single value  but in this case the single value happens to be an array  and as we pass over each character we append it to the last item in that array   Once the last item in the array reaches the target length  we append a new array item

[javascript] How can I split a string into segments of n characters?

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