- var_export: documentation ( source)
- preg_split: documentation ( source)
<?php
$longString = 'I like apple. You like oranges. We like fruit. I like meat, also.';
$maxLength = 18;
var_export(
preg_split("/.{0,{$maxLength}}\K(\s+|$)/", $longString, 0, PREG_SPLIT_NO_EMPTY)
);