pythonlistreorderlist

What is a proper way to re-order the values of a list inside a list?

I would like to re-order the values of the lists inside a_list.

This is my current snippet:

a_list = [["a", "b", "c"], ["a", "b", "c"], ["a", "b", "c"]]
order = [1, 0, 2]

a_list = [a_list[i] for i in order] 

print(a_list)

This is my current output:

[['a', 'b', 'c'], ['a', 'b', 'c'], ['a', 'b', 'c']]

This is my desired output:

[['b', 'a', 'c'], ['b', 'a', 'c'], ['b', 'a', 'c']]
Solution

  • You need to access each sublist of a_list, and then reorder within that sublist. Using list comprehension, it would be like:

    a_list = [["a", "b", "c"], ["a", "b", "c"], ["a", "b", "c"]]
order = [1, 0, 2]

a_list = [[sublst[i] for i in order] for sublst in a_list]

print(a_list) # [['b', 'a', 'c'], ['b', 'a', 'c'], ['b', 'a', 'c']]

    Your current code reorders the sublists themselves; i.e., for example, if you started with

    a_list = [['a', 'b', 'c'], ['d', 'e', 'f'], ['g', 'h', 'i']]

    then the result would have been

    [['d', 'e', 'f'], ['a', 'b', 'c'], ['g', 'h', 'i']]