PHP: str_split

Description

array str_split ( string string [, int split_length] )

Converts a string to an array. If the optional split_length parameter is specified, the returned array will be broken down into chunks with each being split_length in length, otherwise each chunk will be one character in length.

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

Przykład 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);



?>

Output may look like:

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
)

Przykład 2. Examples related to str_split()


<?php



$str = "Hello Friend";



echo $str{0};  // H

echo $str{8};  // i



// Creates: array('H','e','l','l','o',' ','F','r','i','e','n','d')

$arr1 = preg_split('//', $str, -1, PREG_SPLIT_NO_EMPTY);



?>

User Contributed Notes


Another piece of code to replicate str_split() behaviour in PHP 4. No crazy explodes, unpacking or regular expressions.



<?php



   if (!function_exists('str_split')){

      function str_split($string, $split_length=1){



         if ($split_length < 1){

            return false;

         }



         for ($pos=0, $chunks = array(); $pos < strlen($string); $pos+=$split_length){

            $chunks[] = substr($string, $pos, $split_length);

         }

         return $chunks;

      }

   }



?>


It seems that most the str_split imitations around here are pretty weird.



chunk_split can be used for the exact same purpose:

<?php

if (!function_exists('str_split')) {

    function str_split($string, $split_length = 1) {

        return explode("\r\n", chunk_split($string, $split_length));

    }

}

?>



I would not say that it is beautiful, yet it is not as insane as that unpack thing down a few comments.



You can probably improve it by checking $split_length and such, but this Just works (tm) and I doubt that you ever call it with a negative $split_length anyway... Unless you are insane of course.


Here a way to do it using * unpack() *



1. get the size of the string.

2. divide the string length by the character length to split the string at.

3. then build the unpack() to do the multi sub string.

4. use array_combine (because unpack() starts at array element 1)

5. return the split string as a array!



<?



// string to split



$text = 'The cat in the hat. Green eggs and ham. Sam I am.';



// split string at number of characters



$split = 20;



// run it...



$out = split_it ( $text, $split );



print_r ( $out );



function split_it ( $str, $max )

{

    $r = strlen ( $str );



    if ( $r <= $max )

    {

        return ( array ( $str ) );

    }



    $s = array ( 0 );

    $t = '';

    $u = $r / $max;

    $v = '';



    if ( strpos ( $u, '.' ) !== false )

    {

        $p = explode ( '.', $u );



        $u = $p[0];



        $v = 'A' . '* ' . ( $u + 1 ) . '/';

    }



    for ( $i = 1; $i <= $u; $i++ )

    {

        $t .= 'A' . $max . ' ' . $i . '/';

        $s[] = $i;



    }



    $t .= $v;



    return ( array_combine ( $s, unpack ( $t, $str ) ) );

}



?>


If you just need to split strings, and not depend on any other side effects or the like, I have the following in my standard functions file that I use for both PHP4 and PHP5 projects:



if(!function_exists('str_split'))

{

  function str_split($str, $len = 1)

    {

      return(explode("\1\2\3",chunk_split($str, $len, "\1\2\3")));

    }

}


My version of str_split() for PHP < 5:



<?php



if ( !function_exists('str_split') )

{

    function str_split($string, $split_length = 1)

    {

        $array = array();

        $strlen = strlen($string);



        // Original function returns FALSE if $split_length is < 1

        if ( $split_length < 1 )

        {

            return false;

        }



        // If the split length will let the string fit in one array key, don't even bother

        if ( $split_length >= $strlen )

        {

            return array($string);

        }



        for ( $i = 0, $key = 0, $count = 0; $i < $strlen; $i++, $count++ )

        {

            // Count keeps track of when we've reached the split length

            if ( $count >= $split_length )

            {

                $count = 0;

                // When the split length is reached, use the next key

                $key++;

            }

            

            // Protection against E_NOTICE undefined offset

            // isset() is faster than array_key_exists()

            if ( isset($array[$key]) )

            {

                $array[$key] .= $string{$i};

            }

            else

            {

                $array[$key] = $string{$i};

            }

        }

        

        return $array;

    }

}



?>


This is some modification to funcion of ing_rivera.



Now you can use 

  splitstring($string);

  splitstring($string, $length);



<?php

function splitstring($string,$len=0) 

{

  if($len != 0)

  {

    for($i=0;$i<ceil(strlen($string)/$len);$i++)

      $rtnarr[$i]=substr($string, $len*$i, $len);

  }

  else

  {

    for($i=0;$i<strlen($string);$i++)

      $rtnarr[$i]=substr($string, $i, 1);

  }

  return($rtnarr);

}

?>


str_split For PHP versions < 5.0

///////////////////////////////////////////////////////////////

//Converts a string to an array. The returned array will be 

//broken down into chunks with each being $len in length

///////////////////////////////////////////////////////////////

function splitstring($string,$len) {



for($i=0;$i<ceil(strlen($string)/$len);$i++) 

   $rtnarr[$i]=substr($string, $len*$i, $len); 



return($rtnarr);



}


i found this to be the best solution for emulation of the str_split function



if (!function_exists('str_split')){

    function str_split($string, $max_length = 1){

        for($i = 0, $cur_length = 0, $cur_array = 0, $spl_string = array(0 => ''); isset($string{$i}); $i++, $cur_length++){

            if ($cur_length >= $max_length){

                $cur_length = 0;

                $cur_array++;

                $spl_string[$cur_array] = $string{$i};

            }

            else{

                $spl_string[$cur_array] .= $string{$i};

            }

        }

        return($spl_string);

    }

}


katoda's function seems to loose part of the string while splitting.

i.e a md5 string splitted into 4 chars lenght strings will lost half its content (32 chars => 16 chars).



Here's a working one (made by nic58) : 



<?php

function split_str($str, $num = 1)

{

    $arr = array();

    for($i = 0, $len = strlen($str), $j = -1; $i < $len; $i++)

    {

        if(($i % $num) == 0)

        {

            $j++;

        }

        $arr[$j] .= $str[$i];

    }

    return $arr;

}

?>


This is a little function to split a string into shorter strings with max lenght $n in such way, that it don't split words (it search for spaces), it's usefull for articles or sth.


Result is put in $ttab variable, and function result is number of "pages".





<?php


function divide_text($text, $n, &$ttab) {


    


    $ttab = array();


    $l = strlen($text); // text length


    $cb = 0;    //copy begin from..


    $p = 0; // parts


    


    if ($l  <= $n) {


        $ttab[0] = $text;


        return 1;


    } else {


        $ctrl = 1;


        while(((($p-1) * $n) < $l) && ($ctrl < 100)) {


        $crtl++; // control variable, to protect from infinite loops


        


        $tmp = substr($text, $cb, $n);


        


        // we're looking for last space in substring


        $lastpos = strrpos($tmp," ");    


        


        if ( (is_bool($lastbool) && !$lastpos) || ( $l - $cb <= $n)) {


            $ttab[$p] = $tmp;


                        


        } else  {


            $tmpgood = trim(substr($tmp, 0,$lastpos));  // if they were another spaces at the end..


            $ttab[$p] = $tmpgood;


            $cb += $lastpos + 1 ;


            


        }; // if


        $p++;


        }; //for


        return $p;


    }; // if


    





} // divide text





?>


It's best not to overcomplicate things with redundant PHP-side loops and start taking into consideration of preg_split() to simulate str_split()'s behavior for < PHP 5 versions. http://www.php.net/preg-split has an example of how to split strings by one character, but with a little regex knowledge you can easily use a quantifier to split by as many characters as you want.