Joining byte list with python
PythonListJoinBytePython Problem Overview
I'm trying to develop a tool that read a binary file, makes some changes and save it. What I'm trying to do is make a list of each line in the file, work with several lines and then join the list again.
This is what I tried:
file = open('myFile.exe', 'r+b')
aList = []
for line in f:
aList.append(line)
#Here im going to mutate some lines.
new_file = ''.join(aList)
and give me this error:
TypeError: sequence item 0: expected str instance, bytes found
which makes sense because I'm working with bytes.
Is there a way I can use join function o something similar to join bytes? Thank you.
Python Solutions
Solution 1 - Python
Perform the join on a byte string using b''.join():
>>> b''.join([b'line 1\n', b'line 2\n'])
b'line 1\nline 2\n'
Solution 2 - Python
Just work on your "lines" and write them out as soon as you are finished with them.
file = open('myFile.exe', 'r+b')
outfile = open('myOutfile.exe', 'wb')
for line in f:
#Here you are going to mutate the CURRENT line.
outfile.write(line)
file.close()
outfile.close()