从文本文件中读取断行

Question

如果我有一个这样的文本文件:

[001]This is line 1.
[002][too long]This is line 2 but it's Tooooo
oooo long!
[003]This is line 3.

我写了一个'for line in fileA'来读取这个文件，如:

for line in fileA:
    ...

现在我需要合并当前行和下一行。找到((太长))> = 0。我该怎么办?

PS:我写:

for line in fileA:
    if line.find("[too long]")>=0:
        loc = fileA.tell()
        fileB = open("file.txt") #open this file again
        fileB.seek(loc)
        line += fileB.readline().strip()

，但它没有工作。为什么?

Answer 1

听起来开销太大，需要额外读取文件。试试这个:

with open('file.txt') as f:
    for line in f:
        if '[too long]' in line:
            line = line.rstrip('rn') + next(f)
        print line

打印

[001]This is line 1.
[002][too long]This is line 2 but it's Tooooooooo long!
[003]This is line 3.

如果在一行中找到[too long]，则追加下一行。也许您想要附加所有其他行，直到一行以[xxx] ?

Answer 2

您可以使用列表推导将所有行放到一个列表中，这与eumiros的答案非常相似。

with open('file.txt') as f:
    lines = [line.rstrip('rn') + next(f) if '[too long]' in line else line for line in f]

则输出为:

>>> lines
    ['[001]This is line 1.n', "[002][too long]This is line 2 but it's Tooooooooo long!n", '[003]This is line 3.n']

Answer 3

我不确定实际文件的样子，但我可能会这样做:

contents = """[001]This is line 1.
[002][too long]This is line 2 but it's Tooooo
oooo long!
[003]This is line 3.
"""
lines = iter( contents.split("n") )
def fix_file( lines ):
    prev = ''
    number = 1
    for line in lines:
        if not line.startswith( '[{0:03d}]'.format( number ) ):
            prev += line
        else:
            yield prev
            number = number + 1
            prev = line
    yield prev
for line in fix_file( lines ):
    print line