Compare two different files line by line in python

Question

I have two different files and I want to compare theirs contents line by line, and write their common contents in a different file. Note that both of them contain some blank spaces. Here is my pseudo code:

file1 = open('some_file_1.txt', 'r') file2 = open('some_file_2.txt', 'r') FO = open('some_output_file.txt', 'w')  for line1 in file1:     for line2 in file2:         if line1 == line2:             FO.write("%s\n" %(line1))  FO.close() file1.close() file2.close() 

However, by doing this, I got lots of blank spaces in my FO file. Seems like common blank spaces are also written. I want to write only the text part. Can somebody please help me.

For example: my first file (file1) contains data:

Config: Hostname = TUVALU  BT: TS_Ball_Update_Threshold = 0.2  BT: TS_Player_Search_Radius = 4  BT: Ball_Template_Update = 0 

while second file (file2) contains data:

Pole_ID      = 2 Width        = 1280 Height       = 1024 Color_Mode   = 0 Sensor_Scale = 1  Tracking_ROI_Size = 4 Ball_Template_Update = 0 

If you notice, last two lines of each files are the same, hence, I want to write this file in my FO file. But, the problem with my approach is that, it writes the common blank space also. Should I use regex for this problem? I do not have experience with regex.

Answer 1

This solution reads both files in one pass, excludes blank lines, and prints common lines regardless of their position in the file:

with open('some_file_1.txt', 'r') as file1:     with open('some_file_2.txt', 'r') as file2:         same = set(file1).intersection(file2)  same.discard('\n')  with open('some_output_file.txt', 'w') as file_out:     for line in same:         file_out.write(line)