如何在不使用explode函数的情况下将字符串转换为php中的数组

I want to convert strings to array without using explode function in php I want output something like this ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 ) but without using explode().

    <?php

     $str="this is string"; 

    ?>

should be like this arr[0]=this arr[1]=is arr[2]=string

$j = mb_strlen($theString);
for ($k = 0; $k < $j; $k++) 
{
    $char = mb_substr($theString, $k, 1);
    $var_arr[$k] =  $char;
}

The above code don't use any pattern to split the string.

It ttakes one character at a time

EDIT suppose you have string

$s = 12.3.4.09.20

it will give the array as

array = ('1','2','.','3','.','4','.','0','9','.','2','0');

EDIT : COMPLETE CODE

<?php
$theString = "1.2.34.87";
$var_arr = array();
$j = mb_strlen($theString);
for ($k = 0; $k < $j; $k++) 
{
    $char = mb_substr($theString, $k, 1);
    $var_arr[$k] =  $char;
}
print_r($var_arr);
?>

go to http://phpfiddle.org/ and test over there

check the images as a proof

I hope your pattern is like below "this is string" hence following code can be used for same:

<?php
// split the phrase by any number of commas or space characters,
// which include " ", , \t, 
 and \f
$keywords = preg_split("/ /", "this is string");
print_r($keywords);
?>

Thanks Bishop

My solution for this...

$string = 'This-is-the-string';
$word = '';$warray = array();

for($i=0; $i<strlen($string);$i++){
    if($string[$i]=='-'){$warray[] = $word;$word = '';}
    else $word .= $string[$i];
}

if($word!='')$warray[] = $word;//Last word;

echo "<pre>";print_r($warray);die;

Output

Array
(
    [0] => This
    [1] => is
    [2] => the
    [3] => string
)

    $theString = "this is string";
    $var_arr = array();
    $j = mb_strlen($theString);
    $chars = "";
    for ($k = 0; $k < $j; $k++) 
    {

        $char = mb_substr($theString, $k, 1);
        if($char == " ")
        {
            $var_arr[] =  $chars;
            $chars = "";
        }
        else{
            $chars .= $char;
        }

        if( ($k + 1) == $j)
        {
            $var_arr[] =  $chars;
        }

    }
    print_r($var_arr);

$var = 'Rahul,Rohit,Sumeet,Abhi'; //your string 
$len = strlen($var);
$glue = ','; // place your glue here
$j=0;
for($i=0; $i<= $len;$i++){
    $arr[$j] .= trim($var[$i],$glue);   
    if($var[$i] == $glue){
        $j++;   
        continue;
    }
    else{

    }
}

print_r($arr);