unpack

(PHP 3, PHP 4, PHP 5)

unpack -- Unpack data from binary string

说明

array unpack ( string format, string data )

Unpacks from a binary string into an array according to the given format.

unpack() works slightly different from Perl as the unpacked data is stored in an associative array. To accomplish this you have to name the different format codes and separate them by a slash /.

参数

format

See pack() for an explanation of the format codes.

data

The packed data.

返回值

Returns an associative array containing unpacked elements of binary string.

范例

例 1. unpack() example

<?php
$array
= unpack("c2chars/nint", $binarydata);
?>

The resulting array will contain the entries "chars1", "chars2" and "int".

注释

小心

Note that PHP internally stores integral values as signed. If you unpack a large unsigned long and it is of the same size as PHP internally stored values the result will be a negative number even though unsigned unpacking was specified.

参见

pack()