如果它们存在于另一个 txt 文件中，如何从 txt 文件中删除它们

Question

File1.txt contains

text line 1
text line 2
text line 3

File2.txt contains

text line 3 
text line 4
text line 5

I wan't to make a file that contains

text line 1
text line 2

so basically If line exists on file2.txt remove it from file1.txt

I tried playing around with .readlines statements and if statements inside a for loop with no success

Answer 1

Assuming both files are small enough that they can comfortably fit into memory, you could just read both files into a list and then find the difference:

list1 = []
list2 = []

with open("file1.txt") as f:
    list1 = f.readlines()

with open("file2.txt") as f:
    list2 = f.readlines()

list_diff = list(set(list1) - set(list2))

You may then write list_diff to an output file, print it, etc.