Mapping a nested list with List Comprehension in Python?

Question

I have the following code which I use to map a nested list in Python to produce a list with the same structure.

>>> nested_list = [[\'Hello\', \'Wo         


        

Answer 1

Here is solution for nested list that has arbitrary depth:

def map_nlist(nlist=nlist,fun=lambda x: x*2):
    new_list=[]
    for i in range(len(nlist)):
        if isinstance(nlist[i],list):
            new_list += [map_nlist(nlist[i],fun)]
        else:
            new_list += [fun(nlist[i])]
    return new_list

you want to upper case all you list element, just type

In [26]: nested_list = [['Hello', 'World'], ['Goodbye', [['World']]]]
In [27]: map_nlist(nested_list,fun=str.upper)
Out[27]: [['HELLO', 'WORLD'], ['GOODBYE', [['WORLD']]]]

And more important, this recursive function can do more than this!

I am new to python, feel free to discuss!