Recursive function returns None in list

Asked Jun 30 '20 at 21:26

Active Aug 12 '22 at 23:36

Viewed 32 times

flat_list=[]
        
def rec_flatten(alist):
    for i in alist:
        if i == None:
            return
        if type(i)==list:
            flat_list.append(rec_flatten(i))
        else:
            flat_list.append(i)
    return

rec_flatten(['a',['b','c'],'d',['e','f',['g','h']]])
print(flat_list)

Gives:

['a', 'b', 'c', None, 'd', 'e', 'f', 'g', 'h', None, None]

How do I change this function so that the None returns aren't added to the list?

edited Jun 30 '20 at 21:59

asked Jun 30 '20 at 21:26

Cosmo

Because `rec_flatten` always returns `None`... – juanpa.arrivillaga Jun 30 '20 at 21:33
2

Your return statements are blank. These will implicitly return `None`. – pylang Jun 30 '20 at 21:34
Just change this line `flat_list.append(rec_flatten(i))` to this `rec_flatten(i)` – Peaceful James Jun 30 '20 at 22:11

Recursive function returns None in list

0 Answers0