遍历列表索引

Question

I have a list of integers and I want to iterate over it changing some items in place:

for i in xrange(len(items)):
    ...
    items[i] += step

I don't like this xrange(len(items)) . I could do for i, _ in enumerate(items) , but this is also not perfect.

What do you do in such cases?

Answer 1

You can use list comprehension if this is a simple change:

items = [x + step for x in items]

If you can't write it as a list comprehension, enumerate is the way to go:

for i, n in enumerate(items):
    ...
    items[i] = n + step

Answer 2

another way is to use numpy arrays. with them, it's as easy as:

array += step