如何创建两个变量列表？

Question

I know the usual way in Python of creating a 2d list is by making a list of lists and accessing an element with foo[3][2] . However, when performing some operations needed for AES, it would be helpful to use foo[-1][2] , which would be a column of the data ( -1 is every value).

Would it be possible to set up a 2d list using the format foo[3, 2] free from object-oriented classes, or not? Side note: the only time I've ever seen this is in the PILLOW Image library for Python, however it was used in a class, and I don't know how to isolate just what I want.

Answer 1

There is no magic 'all values' built-in for lists... but:

You can write things like bar(foo[*]) as map(bar, foo) or [bar(x) for x in foo] .

For example, foo[*][2] can be [x[2] for x in foo] .

Another option when trying to get columns is to transpose the results (though consider using numpy et al. at this point). You can do this with list(zip(*foo)) , as mentioned by @gelonida.

If you are willing to use classes or helpers then you have many other options to get the syntactic sugar you desire.