在两个单独的列表上使用相同的列表推导

Question

This feels like a simple question, but I haven't been able to figure it out and I haven't been able to find the answer anywhere.

In one line, how can I use two identical list comprehensions on two different lists, and return the results as two seperate lists?

I am trying to do this:

listx = [x for x in listx if x != None]
listy = [y for y in listy if y != None]

Is there a way to do this in one line? Perhaps using map() or a list comprehension?

Answer 1

虽然我不明白为什么它必须是单行，但这应该做你想要的：

listx, listy = [[x for x in alist if x != None] for alist in [listx, listy]]

Answer 2

I think the original one and nested list comprehension is just fine and very readable.

However, if you want to think in terms of functions having an input and output:

You want to filter some contents from a list, so it can be written as:

listx = filter(None, listx)
listy = filter(None, listy)

There is a repeated pattern. The pattern here is we are changing multiple lists at once.

map(function, collection)

So you can break down your original problem to map multiple lists using a filter .

listx, listy = map(lambda x: filter(None, x), [listx, listy])

Answer 3

很简单：

listx, listy = [x for x in listx if x != None], [y for y in listy if y != None]