将列表中的连续数字求和.Python [英] Sum consecutive numbers in a list. Python

问题描述

我正在尝试对列表中的连续数字求和，同时保持第一个数字相同.

i'm trying to sum consecutive numbers in a list while keeping the first one the same.

因此在这种情况下5将保持为5，10将为10 + 5(15)，而15将为15 + 10 + 5(30)

so in this case 5 would stay 5, 10 would be 10 + 5 (15), and 15 would be 15 + 10 + 5 (30)

x = [5,10,15]
y = []

for value in x:
   y.append(...)

print y

[5,15,30]

推荐答案

您要

You want itertools.accumulate() (added in Python 3.2). Nothing extra needed, already implemented for you.

在不存在此功能的早期Python版本中，您可以使用给定的纯python实现:

In earlier versions of Python where this doesn't exist, you can use the pure python implementation given:

def accumulate(iterable, func=operator.add):
    'Return running totals'
    # accumulate([1,2,3,4,5]) --> 1 3 6 10 15
    # accumulate([1,2,3,4,5], operator.mul) --> 1 2 6 24 120
    it = iter(iterable)
    total = next(it)
    yield total
    for element in it:
        total = func(total, element)
        yield total

这将与任何可迭代的，懒惰的和有效的完美配合. itertools 实现在较低的级别上实现，因此甚至更快.

This will work perfectly with any iterable, lazily and efficiently. The itertools implementation is implemented at a lower level, and therefore even faster.

如果您希望将其作为列表，那么自然只需使用内置的 list(): list(accumulate(x)).

If you want it as a list, then naturally just use the list() built-in: list(accumulate(x)).

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