Generate a single-byte string from a number (original) (raw)

chr

(PHP 4, PHP 5, PHP 7)

chr — Generate a single-byte string from a number

Description

chr ( int $bytevalue ) : string

This can be used to create a one-character string in a single-byte encoding such as ASCII, ISO-8859, or Windows 1252, by passing the position of a desired character in the encoding's mapping table. However, note that this function is not aware of any string encoding, and in particular cannot be passed a Unicode code point value to generate a string in a multibyte encoding like UTF-8 or UTF-16.

This function complements ord().

Parameters

bytevalue

An integer between 0 and 255.

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;

Return Values

A single-character string containing the specified byte.

Examples

Example #1 chr() example

`<?php
// Assumes the string will be used as ASCII or an ASCII-compatible encoding$str = "The string ends in escape: "; str.=chr(27);/∗addanescapecharacterattheendofstr .= chr(27); /* add an escape character at the end of str.=chr(27);/∗addanescapecharacterattheendofstr */

/* Often this is more useful */

$str = sprintf("The string ends in escape: %c", 27);
?> `

Example #2 Overflow behavior

<?php echo chr(-159), chr(833), PHP_EOL; ?>

The above example will output:

Example #3 Building a UTF-8 string from individual bytes

<?php $str = chr(240) . chr(159) . chr(144) . chr(152); echo $str; ?>