Usage of struct. Unpack in Python

Usage of struct. Unpack in Python 4/25/2009 12:18:21

In python, the sub-string in a string is extracted in a certain format. It is very efficient to use struck. Unpack. 1. Set the fomat format as follows: # Take the first five characters, skip the 4-character period, and then take 3 Characters Format = '5s 4x 3s' 2. Use struck. Unpack to obtain the sub-string import struct Print struct. Unpack (format, 'test astring ') # ('Test', 'in ') Let's take a simple example. There is a string 'He is not very happy '. After processing it, remove the not in the middle and then output it. Import struct Thestring = 'He is not very happy' Format = '2s 1X2 S 5x 4S 1x 5s' Print ''. Join (struct. Unpack (format, thestring )) Output result: He is very happy reads a binfile using unpack (). rawstring is a STR string: rawfile = open ("LCD. Raw", "rb ") Rawstring = rawfile. Read () rawdata = struct. Unpack (LEN (rawstring) * 'B', rawstring)

Convert rawstring to byte type data to obtain a rawdata tuples for processing.

Format	C type	Python	Notes
X	Pad byte	No value
C	Char	String of length 1
B	Signed Char	Integer
B	Unsigned char	Integer
H	Short	Integer
H	Unsigned short	Integer
I	Int	Integer
I	Unsigned int	Long
L	Long	Integer
L	Unsigned long	Long
Q	Long long	Long	(1)
Q	Unsigned long	Long	(1)
F	Float	Float
D	Double	Float
S	Char []	String
P	Char []	String
P	Void *	Integer