Perl 中的 unpack函数

描述

此函数使用TEMPLATE中指定的格式解压缩二进制字符串STRING。基本上颠倒打包的操作,根据提供的格式返回打包值的列表。

You can also prefix any format field with a %<number> to indicate that you want a 16-bit checksum of the value of STRING, instead of the value.

语法

以下是此函数的简单语法-

unpack TEMPLATE, STRING

返回值

此函数返回未打包值的列表。

下表列出了在TEMPLATE中使用的值。

例

以下是显示其基本用法的示例代码-

#!/usr/bin/perl -w

$bits=pack("c", 65);
# prints A, which is ASCII 65.
print "bits are $bits\n";
$bits=pack( "x" );
# $bits is now a null chracter.
print "bits are $bits\n";
$bits=pack( "sai", 255, "T", 30 );
# creates a seven charcter string on most computers'
print "bits are $bits\n";

@array=unpack( "sai", "$bits" );

#Array now contains three elements: 255, A and 47.
print "Array $array[0]\n";
print "Array $array[1]\n";
print "Array $array[2]\n";

执行上述代码后,将产生以下输出-

bits are A
bits are 
bits are ?T-
Array 255
Array T
Array 30