迭代元组列表 [英] Iterate a list of tuples

问题描述

我正在寻找一种干净的方法来遍历一个元组列表，其中每个都是一对，如此 [（a，b），（c，d）...] 。最重要的是，我想改变列表中的元组。

I'm looking for a clean way to iterate over a list of tuples where each is a pair like so [(a, b), (c,d) ...]. On top of that I would like to alter the tuples in the list.

标准做法是避免更改列表同时迭代它，所以我该怎么办？这就是我想要的：

Standard practice is to avoid changing a list while also iterating through it, so what should I do? Here's what I kind of want:

for i in range(len(tuple_list)):
  a, b = tuple_list[i]
  # update b's data
  # update tuple_list[i] to be (a, newB)

推荐答案

只需替换列表中的元组即可;只要您避免添加或删除元素，可以在循环时修改列表：

Just replace the tuples in the list; you can alter a list while looping over it, as long as you avoid adding or removing elements:

for i, (a, b) in enumerate(tuple_list):
    new_b = some_process(b)
    tuple_list[i] = (a, new_b)

或者，如果您可以将对 b 的更改汇总到我上面所做的函数中，请使用列表理解：

or, if you can summarize the changes to b into a function as I did above, use a list comprehension:

tuple_list = [(a, some_process(b)) for (a, b) in tuple_list]

这篇关于迭代元组列表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！