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This article will explain in detail how to understand the binary conversion module of python. The content of the article is of high quality, so the editor shares it for you as a reference. I hope you will have a certain understanding of the relevant knowledge after reading this article.

In pyton, binary is converted by struct module, which mainly includes two kinds of functions, namely, pack for packaging and unpack for unpacking.

Among them, the input format of struct.pack is struct.pack (format, v1 Magi v2,...), where format is a format string, v1 Magi v2. Is the character that will be converted to bytes.

For example

> import struct > struct.pack ('iii', 15) b'\ X0f\ X00\ X00\ x00' > > struct.pack ('iii', 15,16,17) b'\ X0f\ X00\ X11\ X00\ x00 > > struct.pack ('breadth, 255) # b format values range from-128to 127struct.error: byte format requires-128> struct.pack (' breadth, 2005) b'\ xc8' > struct.pack ('B' B') 71) within # 128, you can use ASCII to denote baked G'.

I represents the binary code corresponding to int,15 F000, so its output is b\ x0f\ x00\ x00. When the format string is iii, it indicates that you want to convert three numbers to binary in the type of integer.

Each character in the formatted string represents a data type, in which the characters related to the integer type are as follows, the signed integer on the left and the unsigned integer on the right

C language type C language type standard size bsigned charBunsigned char1hshortHunsigned short2iintIunsigned int4llongLunsigned long4qlong longQunsigned long long8nssize_tNsize_t

Other types

Format C type Python type standard size x fill byte no byte string with cchar length 1? _ Boolbool1efloat2ffloatfloat4ddoublefloat8schar [] byte string pchar [] byte string Pvoid* integer

The function to get the standard size is provided in struct, calcsize:

> struct.calcsize ('B') 1 > struct.calcsize ('i') 4

In addition to declaring the data type when formatted, struct can also specify alignment, such as

> struct.pack ("I", 15) b'\ x0f\ x00\ x00\ x00' > > struct.pack ("> I", 15) # small end sequence b'\ x00\ x00\ x0f' > > struct.pack ("

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