列表中连续元素之间的差异 [英] Difference between consecutive elements in list

问题描述

可能重复:
Python-列表元素之间的差异

Possible Duplicate:
Python - Differences between elements of a list

我有一个列表，我想找到连续元素之间的区别:

I have a list and I want to find difference between consecutive elements:

a = [0, 4, 10, 100]
find_diff(a)
>>> [4,6,90]

您如何编码find_diff()函数?我可以使用"for"迭代器对此进行编码，但是我敢肯定，有一种非常简单的方法可以使用一个简单的内衬来实现它.

How would you code find_diff() function? I can code this with "for" iterator but I am sure there are very simple ways to do it with a simple one liner.

推荐答案

您可以使用> c0> ， zip 和列表理解:

>>> a = [0, 4, 10, 100]

# basic enumerate without condition:
>>> [x - a[i - 1] for i, x in enumerate(a)][1:]
[4, 6, 90]

# enumerate with conditional inside the list comprehension:
>>> [x - a[i - 1] for i, x in enumerate(a) if i > 0]
[4, 6, 90]

# the zip version seems more concise and elegant:
>>> [t - s for s, t in zip(a, a[1:])]
[4, 6, 90]

在性能方面，似乎没有太多差异:

Performance-wise, there seems to be not too much variance:

In [5]: %timeit [x - a[i - 1] for i, x in enumerate(a)][1:]
1000000 loops, best of 3: 1.34 µs per loop

In [6]: %timeit [x - a[i - 1] for i, x in enumerate(a) if i > 0]
1000000 loops, best of 3: 1.11 µs per loop

In [7]: %timeit [t - s for s, t in zip(a, a[1:])]
1000000 loops, best of 3: 1.1 µs per loop

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