Split string into 2 pieces by length using PHP

There is a function called str_split^{PHP Manual} which might, well, just split strings:

$parts = str_split($string, $split_length = 400);

$parts is an array with each part of it being 400 (single-byte) characters at max. As per this question, you can as well assign the first and second part to individual variables (expecting the string being longer than 400 chars):

list($str_1, $str_2) = str_split(...);

$first400 = substr($str, 0, 400);
$theRest = substr($str, 400);

You can rename your variables to whatever suits you. Those names are just for explanation. Also if you try this on a string less than 400 characters $theRest will be FALSE