how to remove padding in struct python during unpacking

Question

When I use packing in struct, I find out that during unpacking that I have extra characters after I unpack the byte object.

For example before packing: c = b'CONNECT' value gotten after unpacking using struct is b'CONNECT\x00\x00\x00\x00\x00'

Here is my code:

import struct
import datetime
import binascii

string_format = '12s'
s = struct.Struct(string_format)
str = 'CONNECT'
byte = str.encode()
print(byte)

packed_data = s.pack(byte)
print(packed_data)
unpacked_data = s.unpack(packed_data)
unpacked_data = unpacked_data[0]
arr = []

for item in unpacked_data.decode():
    print(item)
    arr.append(item)

print(arr)

How can I get b'CONNECT' after unpacking.

import struct import datetime import binascii string_format = '12s' s = struct.Struct(string_format) str = 'CONNECT' byte = str.encode() print(byte) packed_data = s.pack(byte) print(packed_data) unpacked_data = s.unpack(packed_data) unpacked_data = unpacked_data[0] arr = [] for item in unpacked_data.decode(): print(item) arr.append(item) print(arr) — Francis, Apr 20 '18 at 15:41

score 0 · Answer 1 · answered Apr 20 '18 at 16:16

The additional NUL bytes are added because you update the struct format to have 12 characters with '12s'. If you add print('CONNECT'.encode()) before all your statements, you'll see that it's correct.

Since you'll probably want to strip off the additional characters, just use that function:

print(repr(unpacked_data.decode().strip()))          #Prints 'CONNECT'

how to remove padding in struct python during unpacking

1 Answers1