本文介绍了遍历列表一部分的pythonic方法的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我想遍历列表中除前几个元素外的所有内容,例如:
I want to iterate over everything in a list except the first few elements, e.g.:
for line in lines[2:]:
foo(line)
这很简洁,但是复制了整个列表,这是不必要的.我可以做到:
This is concise, but copies the whole list, which is unnecessary. I could do:
del lines[0:2]
for line in lines:
foo(line)
但这会修改列表,但并不总是很好.
But this modifies the list, which isn't always good.
我可以这样做:
for i in xrange(2, len(lines)):
line = lines[i]
foo(line)
但是,那只是毛病.
更好的可能是这样:
for i,line in enumerate(lines):
if i < 2: continue
foo(line)
但这并不像第一个例子那么明显.
But it isn't quite as obvious as the very first example.
因此:有什么方法可以像第一个示例一样显而易见,但是不会不必要地复制列表?
So: What's a way to do it that is as obvious as the first example, but doesn't copy the list unnecessarily?
推荐答案
您可以尝试 itertools.islice(iterable[, start], stop[, step])
:
You can try itertools.islice(iterable[, start], stop[, step])
:
import itertools
for line in itertools.islice(list , start, stop):
foo(line)
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