1

The first file contains the following IP addresses: 10.0.0.1 and 10.0.0.2 and the second file contains: 10.0.0.1 and 192.168.1.1. My tiny script should display the difference between file 1 and file 2. According to my example, the output should be 10.0.0.2.

file1 = input('Filename1: ')
f = open(file1,'r')
lines1  = f.readlines() 

file2 = input('Filename2: ')
g = open(file2,'r')
lines2  = g.readlines()

for line1 in lines1:
    for line2 in lines2:
        if line1 != lines2:
            print(line1)

When i run the code i get:

Filename1: l1.txt
Filename2: l2.txt
10.0.0.1

10.0.0.1

10.0.0.2
10.0.0.2

Any ideas what is wrong ?

zimskiz
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4 Answers4

1

1)Create two sets namely s1 and s2. 2) Updates the contents of file1 and file2 in the respective sets. 3) there is method called set1.difference(set2) which gives you expected output.

naga ranjith
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1

Use set to compare occurrences of entities:

file1 = "f1.txt"
f = open(file1,'r')
lines1  = f.read().splitlines() 

file2 = "f2.txt"
g = open(file2,'r')
lines2  = g.read().splitlines()

differences = set(lines1) - set(lines2)
print("\n".join(differences))

output:

10.0.0.2
Tim
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  • If I add more IP addresses to file1, I get a blank space in front of each result. I'm not sure why is this happening. Also, i tried to add a comma after each line with +',' and it doesn't work as well. Any ideas? – zimskiz Nov 21 '19 at 10:00
  • That's better :). How can I add a comma after each IP address found different?`m.write("\n".join(differences)+',')` --> it doesn't add a comma and the end of each line. – zimskiz Nov 21 '19 at 10:05
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    This is another question :) Please upvote/accept answer. To separate results with a comma and a space instead of a newline, use `print(", ".join(differences))`. – Tim Nov 21 '19 at 10:14
  • @zimskiz don't forget to pick up an answer to accept. – Tim Nov 21 '19 at 20:52
1

You are comparing each line of one file with each line of the other file, that leads to errors. You need to use sets:

f1Content = set(open('l1.txt').read().splitlines())
f2Content = set(open('l2.txt').read().splitlines())
print(f1Content.difference(f2Content))

Output:

set(['10.0.0.2'])
Maurice Meyer
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    `f1Content = set(open('l1.txt').readlines())` will work as well. Also, we're assuming the two files are small enough to fit into memory) – ChatterOne Nov 21 '19 at 09:37
1

Looks like this is what you wanted:

with open("f1.txt",'r') as f:
    lines1  = f.readlines()
lines1 = [line.strip() for line in lines1]

with open("f2.txt",'r') as f:
    lines2  = f.readlines()
lines2 = [line.strip() for line in lines2]


for line in lines1:
    if line not in lines2:
        print(line)


##You can do it by set operations as well
print(set(lines1).difference(set(lines2)))
hunaif
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