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    str_split

    (PHP 5, PHP 7, PHP 8)

    str_split — Convert a string to an array

    Description

    str_split(string $string, int $length = 1): array

    Converts a string to an array.

    Parameters

    string

    The input string.

    length

    Maximum length of the chunk.

    Return Values

    If the optional length parameter is specified, the returned array will be broken down into chunks with each being length in length, except the final chunk which may be shorter if the string does not divide evenly. The default length is 1, meaning every chunk will be one byte in size.

    Errors/Exceptions

    If length is less than 1, a ValueError will be thrown.

    Changelog

    Version Description
    8.0.0 If length is less than 1, a ValueError will be thrown now; previously, an error of level E_WARNING has been raised instead, and the function returned false.

    Examples

    Example #1 Example uses of str_split()

    <?php

    $str     = "Hello Friend";

    $arr1 = str_split($str);
    $arr2 = str_split($str, 3);

    print_r($arr1);
    print_r($arr2);

    ?>

    The above example will output:

    Array
(
    [0] => H
    [1] => e
    [2] => l
    [3] => l
    [4] => o
    [5] =>
    [6] => F
    [7] => r
    [8] => i
    [9] => e
    [10] => n
    [11] => d
)

Array
(
    [0] => Hel
    [1] => lo
    [2] => Fri
    [3] => end
)

    Notes

    Note:

    str_split() will split into bytes, rather than characters when dealing with a multi-byte encoded string. Use mb_str_split() to split the string into code points.

    See Also

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    User Contributed Notes 1 note

    up
    -3
    lskatz at gmail dot com
    14 years ago
    A good use of str_split is reverse translating an amino acid sequence.

    <?php
    /* reverse translate an aa sequence using its dna counterpart */
    function reverseTranslate($aaSeq,$ntSeq){
          $nt=str_split($ntSeq,3);
          $aa=str_split($aaSeq,1);
          $gapChar=array('*','-');

          $numAa=count($aa);
          $ntIndex=0;
          $newNtSeq="";
      for(    $i=0;$i<$numAa;$i++){
            // if the aa is a gap, then just put on a gap character
            if(in_array($aa[$i],$gapChar)){
              $newNtSeq.='---';
        }
        else{
              $newNtSeq.=$nt[$ntIndex];
              $ntIndex++;
        }
      }
      return     $newNtSeq;
    }
    ?>
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