Using PHP chunk_split() to Split Strings into Chunks

The chunk_split() function in PHP splits a string into smaller chunks, optionally inserting a specified end sequence after each chunk. It is useful for formatting outputs such as base64‑encoded data to comply with RFC 2045.

Syntax :

string chunk_split(string $body, int $chunklen = 76, string $end = "\r\n")

Parameters :

$body – the string to be split.

$chunklen – the length of each chunk.

$end – the sequence appended after each chunk.

Return value : the resulting string after being split according to the given parameters.

Example 1 – split a short sentence into chunks of six characters, using "..." as the end marker:

<?php
$str = "Hello world!";
echo chunk_split($str, 6, "...");
?>

Output :

Hello ...world!...

Example 2 – split a word into single‑character chunks, using a period as the end marker:

<?php
$str = "Shanghai";
echo chunk_split($str, 1, ".");
?>

Output :

S.h.a.n.g.h.a.i.