Python，如何从另一个文本文件中的文本中删除文本？

Question

Kind of hard to explain, but I have in a script a text file that will have a bunch of characters. I also will have another master record of everything. I want to take the first file and remove everything that is matching with the master record. Some entries will eventually not appear in the first file at all. Here's kind of an example:

First file:

Cow 
Duck
Sheep

Master Record:

Duck
Sheep 
Cat
Dog

Any help is appreciated!

Answer 1

Read though the master file and put the lines into a set, then compare the lines in the second file to the words in the master set:

Code:

# read in the master file and put each line into a set
with open('master') as f:
    master = {w.strip() for w in f.readlines()}

# read through the second file and keep each line not in master
with open('file1') as f:
    allowed = [w.strip() for w in f.readlines() if w.strip() not in master]

# show the allowed lines
for w in allowed:
    print(w)

Answer 2

Try this (assuming both your lists are files):

master = open('master.txt', 'r').read()
f = open('file.txt', 'r').read()
f_arr = f.split('\n')
master_arr = master.split('\n')
fin_arr = []
for i in range(len(f_arr)):
    if not f_arr[i] in master_arr:
         fin_arr.append(f_arr[i])
final = '\n'.join(fin_arr)

Answer 3

Note, this does not include the file reading/writing.

The data:

file = """
cow
duck
sheep
"""

master_record = """
duck
sheep
cat
dog
"""

Now for the one-liner list comprehension no one wants to look at:

print([i for i in [x for x in file.replace('\n', ' ').split(' ') if x in master_record.replace('\n', ' ').split(' ')] if i])

That will return a list of all the words in file that also appear in the master record.

Splitting it up:

found = []

# Loop through ever word in `file`, replacing newlines with spaces,
for word in file.replace('\n', ' ').split(' '):
    # Check if the word is in the master file,
    if word in master_record.replace('\n', ' ').split(' '):
        # Make sure the word contains something,
        if word:
            # Add this word to found,
            found += [word]

# Print what we found,
print(found)

Hope this helps!

-Coolq