python - 从文本文件中读取虚线

Question

如果我有这样的文本文件：

[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，比如：

for line in fileA:
    ...

现在我需要在 line.find("[too long]")>=0 时合并当前行和下一行。我应该怎么做？

PS：我写道：

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()

但它没有用。为什么？

Answer 1

额外读取文件听起来开销太大。试试这个：

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

印刷

[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[too long]中找到，则会附加以下行。也许您想追加所有其他行，直到一行以[xxx]?

Answer 2

您可以使用列表推导将所有行添加到列表中，执行与 eumiros 答案非常相似的操作。

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

然后输出是：

>>> 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，但我可能会使用这样的东西：

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

这样你就不需要额外的内容了。