python - 如何使用 python grep 大文件中两个模式之间的行

Question

我有一个非常大的文件，像这样:

[PATTERN1]
line1
line2
line3 
...
...
[END PATTERN]
[PATTERN2]
line1 
line2
...
...
[END PATTERN]

I need to extract in another file, lines between a variable starter pattern [PATTERN1] and another define pattern [END PATTERN], only for some specific starter pattern.
For example:

[PATTERN2]
line1 
line2
...
...
[END PATTERN]

I already do the same thing, with a smaller file, using this code:

FILE=open('myfile').readlines()

newfile=[]
for n in name_list:
    A = FILE[[s for s,name in enumerate(FILE) if n in name][0]:]
    B = A[:[e+1 for e,end in enumerate(A) if 'END PATTERN' in end][0]]
    newfile.append(B)

其中“name_list”是包含我需要的特定起始模式的列表。

有效!!但我想有一种更好的方法可以在不使用 .readlines() 命令的情况下处理大文件。
任何人都可以帮助我吗？

非常感谢!

Answer 1

考虑:

# hi
# there
# begin
# need
# this
# stuff
# end
# skip
# this

with open(__file__) as fp:
    for line in iter(fp.readline, '# begin\n'):
        pass
    for line in iter(fp.readline, '# end\n'):
        print line

打印“需要这个东西”

更灵活(例如允许重新模式匹配)是使用 itertools drop- 和 takewhile:

with open(__file__) as fp:
    result = list(itertools.takewhile(lambda x: 'end' not in x, 
        itertools.dropwhile(lambda x: 'begin' not in x, fp)))