PHP chr() Function

The PHP chr() function returns a character from the specified ASCII value. This function can take ASCII value specified in decimal, octal, or hex values.

• Octal ASCII values start with 0 followed by ASCII value.
• Hex ASCII values start with 0x followed by ASCII value.

This function complements ord() function.

Syntax

chr(ascii)

Parameters

Return Value

Returns a character from the specified ASCII value.

Example: chr() example

In the example below, chr() function returns a character from the specified ASCII value.

<?php
echo chr(65)."\n";
echo chr(0101)."\n";
echo chr(0x41)."\n";
?>

The output of the above code will be:

A
A
A 

Example: overflow behavior

Values outside the valid range (0..255) will be bitwise and'ed with 255, which is equivalent to the following algorithm:

while ($bytevalue < 0) {
  $bytevalue += 256;
}
$bytevalue %= 256;

Consider the example below to understand the above discussed concept.

<?php
echo chr(-185)."\n";
echo chr(71)."\n";
echo chr(327)."\n";
?>

The output of the above code will be:

G
G
G

Example: building a UTF-8 string from individual bytes

Consider one more example where a UTF-8 string is constructed using individual bytes.

<?php
$str1 = chr(240) . chr(159) . chr(152) . chr(142);
echo $str1;

echo "\n";

$str2 = chr(240) . chr(159) . chr(152) . chr(155);
echo $str2;
?>

The output of the above code will be:

😎
😛