Definition and Usage
定义和用法
The pack() function packs data into a binary string.
pack()函数的作用是:将数据压缩成一个二进制字符串。
Syntax
语法
Parameter参数 | Description描述 |
format | Required. Specifies the format to use when packing data. 必要参数。指定用于打包数据的格式。 Possible values: 可用值如下: - a - NUL-padded string
a - NUL- 字符串填满[padded string] - A - SPACE-padded string
A - SPACE- 字符串填满[padded string] - h - Hex string, low nibble first
h – 十六进制字符串,低“四位元”[low nibble first] - H - Hex string, high nibble first
H - 十六进制字符串,高“四位元”[high nibble first] - c - signed char
c – 带有符号的字符 - C - unsigned char
C – 不带有符号的字符 - s - signed short (always 16 bit, machine byte order)
s – 带有符号的短模式[short](通常是16位,按机器字节顺序) - S - unsigned short (always 16 bit, machine byte order)
S – 不带有符号的短模式[short](通常是16位,按机器字节排序) - n - unsigned short (always 16 bit, big endian byte order)
n -不带有符号的短模式[short](通常是16位,按大endian字节排序) - v - unsigned short (always 16 bit, little endian byte order)
v -不带有符号的短模式[short](通常是16位,按小endian字节排序) - i - signed integer (machine dependent size and byte order)
i – 带有符号的整数(由大小和字节顺序决定) - I - unsigned integer (machine dependent size and byte order)
I – 不带有符号的整数(由大小和字节顺序决定) - l - signed long (always 32 bit, machine byte order)
l– 带有符号的长模式[long](通常是32位,按机器字节顺序) - L - unsigned long (always 32 bit, machine byte order)
L – 不带有符号的长模式[long](通常是32位,按机器字节顺序) - N - unsigned long (always 32 bit, big endian byte order)
N – 不带有符号的长模式[long](通常是32位,按大edian字节顺序) - V - unsigned long (always 32 bit, little endian byte order)
V– 不带有符号的长模式[long](通常是32位,按小edian字节顺序) - f - float (machine dependent size and representation)
f –浮点(由大小和字节顺序决定) - d - double (machine dependent size and representation)
d – 双精度(由大小和字节顺序决定) - x - NUL byte
x – 空字节[NUL byte] - X - Back up one byte
X- 后面一个字节[Back up one byte] - @ - NUL-fill to absolute position
@ - NUL- 添加到一个绝对位置[absolute position] |
args+ | Optional. Specifies one or more arguments to be packed 可选参数。指定一个或多个用于打包的自变量 |
Example 1
案例1
<?php
echo pack("C3",80,72,80);
?> |
The output of the code above will be:
上述代码将输出下面的结果:
Example 2
案例2
<?php
echo pack("C*",80,72,80);
?> |
The output of the code above will be:
上述代码将输出下面的结果: