Python - Append particular numpy arrays based on value -

i trying find shorter way write code.

i have 20 folders, each different value in name (1 - 20).

in each folder there text files list of numbers in them. apply function each of these lists , append numpy list, 1 of 20, corresponding number in folder name.

i trying find way append correct numpy array without having have 20 'if...else if' statements checking folder number.

this code feels unnecessarily long , hoping more concise way it.

-------- current psudocode ------

array_one = [] array_two = []   ...  if folder_number == 1:     array_one.append(list_from_folder) elif folder_number == 2:     array_two.append(list_from_folder)  ... 

any recommendations? (using python)

use dictionary:

folder_lists = {num: [] num in range(1, 21)} 

this give key: value mapping data structure in keys (e.g. 1, 2, 3, etc.) correspond folder numbers , values lists map keys (those folders):

{1: [], 2: [], 3: [], ..., 20: []} 

then this:

for f in folders:     folder_number = <insert folder number here>     folder_lists[folder_number].append(list_from_folder)