Python：如何计算文件中的多少行相同

Question

I have a text document in the format of:

-1+1
-1-1
+1+1
-1-1
+1-1
...

I want to have a program that counts how many lines have -1+1 lines and +1-1 lines. The program would then just need to return the value of how many lines are like this. I have written the code:

f1 = open("results.txt", "r")
fileOne = f1.readlines()
f1.close()

x = 0
for i in fileOne:
    if i == '-1+1':
        x += 1
    elif i == '+1-1':
        x += 1
    else:
        continue

print x

But for some reason it always returns 0 and I have no idea why.

Any help would me much appreciated as I have been looking at this for hours!!

Answer 1

Use collections.Counter instead:

import collections

with open('results.txt') as infile:
    counts = collections.Counter(l.strip() for l in infile)
for line, count in counts.most_common():
    print line, count

Most of all, remove whitespace (the newline specifically, but any other spaces or tabs might interfere too) when counting your lines.

Answer 2

.readlines()将\\n .readlines()中，这就是为什么它们不匹配的原因。

Answer 3

If you don't want to import a module, enjoy short code, and like a bit of 'list' comprehension :

with open('results.txt') as infile:
    counts = { key: infile.count(key) for key in ['-1+1', '+1-1'] }

Then of course access counts as a dict