Php/docs/function.chr
chr
(PHP 4, PHP 5, PHP 7)
chr — Generate a single-byte string from a number
Description
chr
( int $codepoint
) : string
Returns a one-character string containing the character specified
by interpreting codepoint
as an unsigned integer.
This can be used to create a one-character string in a single-byte encoding such as ASCII, ISO-8859, or Windows 1252, by passing the position of a desired character in the encoding's mapping table. However, note that this function is not aware of any string encoding, and in particular cannot be passed a Unicode code point value to generate a string in a multibyte encoding like UTF-8 or UTF-16.
This function complements ord().
Parameters
codepoint
An integer between 0 and 255.
Values outside the valid range (0..255) will be bitwise and'ed with 255, which is equivalent to the following algorithm:
while ($bytevalue < 0) { $bytevalue += 256;}$bytevalue %= 256;
Return Values
A single-character string containing the specified byte.
Changelog
Version | Description |
---|---|
7.4.0 | The function no longer silently accepts unsupported codepoint s,
and casts these to |
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); /* add an escape character at the end of $str *//* Often this is more useful */$str = sprintf("The string ends in escape: %c", 27);?>
Example #2 Overflow behavior
<?phpecho chr(-159), chr(833), PHP_EOL;?>
The above example will output:
aA
Example #3 Building a UTF-8 string from individual bytes
<?php$str = chr(240) . chr(159) . chr(144) . chr(152);echo $str;?>
The above example will output:
🐘
See Also
- sprintf() - Return a formatted string with a format string of
%c
- ord()
- An » ASCII-table
- mb_chr()