How Python reads and writes binary files

The examples in this article describe how Python reads and writes binary files. Share to everyone for your reference. Specific as follows:

Beginner python, now to read a binary file, find doc only found that file provides a read and write function, and read and write is a string, if just read and write char, such as a byte of the line, to read and write such as int,double, such as multi-byte data is inconvenient. A post was found online, using the pack and unpack functions inside the struct module to read and write. Write your own code below to verify it.

>>> from struct import *>>> file = open (r "C:/debug.txt", "WB") >>> File.write (Pack ("Idh", 12345, 67.89, ()) >>> File.close ()

And then read it in.

>>> file = open (r "C:/debug.txt", "RB") >>> (a,b,c) = Unpack ("Idh", File.read (8+8+2)) >>> a,b,c (12345, 67.890000000000001, i) >>> print a,b,c12345 67.89 15>>> file.close ()

The size of the data that you need to be aware of during operation

Pay attention to WB,RB in the B word, must not be less

Method 1:

Myfile=open (' c:\\t ', ' RB ') S=myfile.read (1) byte=ord (s) #将一个字节 read into a number of print hex (byte) #转换成16进制的字符串

Method 2

Import structmyfile=open (' c:\\t ', ' RB '). Read (1) Print struct.unpack (' C ', myfile) print struct.unpack (' B ', myfile)

Write

To open a file for binary writing are easy, it's the same-the-mode you do for reading, and just change the "WB".
File = Open ("Test.bin", "WB")
But what do you write the binary byte into the file?
You could write it straight away with hex code like this:
File.write ("\x5f\x9d\x3e") File.close ()
Now, check it out with HexEdit,
HexEdit Test.bin
You'll see this:
00000000 5F 9D 3E _.> 00000020 00000040
Now, open the file to append more bytes:
File = Open ("Test.bin", "AB")
What if I want to store by bin value into a stream and write it one short?
s = "\x45\xf3" s = s + "%c%c"% (0x45,0xf3) file.write (s) file.close ()
Any convenient ways if I can obtained a hex string, and want to convert it back to binary format?
Yes, you just need to import binascii
Import binascii hs= "5b7f888489feda" Hb=binascii.a2b_hex (HS) File.write (HB) File.close ()

Hopefully this article will help you with Python programming.

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