如何只读取特定字符串后的文本文件中的行？

Question

我想将字典中特定字符串之后的所有行读到字典中。我想对数千个文本文件执行此操作。

我可以'Abstract'使用以下代码（从此答案中得到）识别并打印出特定的字符串（）：

for files in filepath:
    with open(files, 'r') as f:
        for line in f:
            if 'Abstract' in line:
                print line;

但是如何告诉Python开始读取仅在字符串之后的行？

Answer 1

当您到达要开始的行时，只需开始另一个循环即可：

for files in filepath:
    with open(files, 'r') as f:
        for line in f:
            if 'Abstract' in line:                
                for line in f: # now you are at the lines you want
                    # do work

文件对象是其自己的迭代器，因此当到达其中的行时，'Abstract'我们将从该行继续进行迭代，直到消耗完迭代器为止。

一个简单的例子：

gen = (n for n in xrange(8))

for x in gen:
    if x == 3:
        print('Starting second loop')
        for x in gen:
            print('In second loop', x)
    else:
        print('In first loop', x)

产生：

In first loop 0
In first loop 1
In first loop 2
Starting second loop
In second loop 4
In second loop 5
In second loop 6
In second loop 7

您还可以使用itertools.dropwhile来消耗所需的行：

from itertools import dropwhile

for files in filepath:
    with open(files, 'r') as f:
        dropped = dropwhile(lambda _line: 'Abstract' not in _line, f)
        next(dropped, '')
        for line in dropped:
                print(line)