Python垂直并排打印灵活数量的列表

Question

I'm new to python and trying to print a few lists side by side vertically eg list_1 = [1,2,3] and list_2 = [4,5] :

Output:

1 4  
2 5  
3 None  

I found that map(None, list_1, list_2) can achieve this.

However, I may have up to >10 lists to print vertically. I wonder if there is some neat way to do this.

Answer 1

You could use map(None, list_1, list_2, list_3, ...) , since map can take an arbitrary number of arguments.

However, it is usually not a good idea to have numbered variable names. It is often a sign that you should be using a list or tuple instead. So instead of having variables list_1 , ..., list_10 , you should have one variable columns which is a list of lists.

If columns = [list_1, list_2] , then

import itertools as IT
rows = IT.izip_longest(*columns)

is equivalent to map(None, list_1, list_2) and is compatible with Python3, which removes the map(None, ...) option. Notice that this notation generalizes well to arbitrary number of lists without requiring you to type all those variable names by hand.

The * in IT.izip_longest(*columns, ...) is Python's unpacking operator . It unpacks the items in columns and sends those items to IT.izip as individual arguments. This notation allows you to send an arbitrary number of arguments to a function.