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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, otherwise each chunk will be one character in length.

false is returned if length is less than 1. If the length length exceeds the length of string, the entire string is returned as the first (and only) array element.

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.

User Contributed Notes 1 note

down

-2

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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