PHP reference

chunk_split

Splits a string into chunks, inserting a separator after each.

Syntax

chunk_split(string $string, int $length = 76, string $separator = "\r\n"): string

stringThe string with separators.

A card number in groups of four digits:

<?php
 
echo trim(chunk_split('4276123456789012', 4, ' '));

Output:

4276 1234 5678 9012

The separator is added after the last chunk too — remove it with trim() or rtrim().

Strings — Working with strings in PHP — quotes, concatenation, length, searching, replacing and multibyte functions.