如何将两个txt文件中具有相同列的数据获取到新的txt？

Question

I need to get over 200,000 annotations from the original annotation txt file(B.txt) by comparing the first column string.

For example:

A.txt is like

00001.jpg

00002.jpg

00004.jpg

...

B.txt is like

00001.jpg 12 3 1 33

00002.jpg 32 4 2 2

00003.jpg 23 4 5 1

00004.jpg 3 5 3 1

00005.jpg 2 4 1 1

...

I want get a C.txt like

00001.jpg 12 3 1 33

00002.jpg 32 4 2 2

00004.jpg 3 5 3 1

...

The code I worte seems like can't get any line wrote in C.txt

alines = open('A.txt', 'r').readlines() 
blines = open('B.txt', 'r').readlines()
fw = open('C.txt', 'w')
for al in alines:
    for bl in blines:
        if str(al) in str(bl):
            fw.write(bl)
fw.close()

Answer 1

Your code doesn't work because alines and blines lists contain the lines ending with the '\n' symbols so the comparison always fails.

The following code strips the '\n' symbols and also eliminates the second "for" cycle:

with open('A.txt', 'r') as fh:
    # Splitlines gets rid of the '\n' endlines
    alines = fh.read().splitlines()
with open('B.txt', 'r') as fh:
    # Splitlines gets rid of the '\n' endlines
    blines = fh.read().splitlines()
with open('C.txt', 'w') as fh:
    for line in blines:
        # Split the file name
        parts = line.split(' ', 1)
        # Look up the filename
        if parts[0] in alines:
            fh.write(line + '\n')