替换列表中的值

Question

Python 3. Windows 10.

I have a hierarchical list and I want to change their values with the values specified.

For example: I have hierarchical list

l = [[[0, 4], 1], [2, 3], 5]]

and I have a dictionary

{0: 'da-1.txt',
 1: 'da-2.txt',
 2: 'en-1.txt',
 3: 'en-2.txt',
 4: 'it-1.txt',
 5: 'it-2.txt'}

I want to replace values of the list with the values of the dictionary correspondingly without breaking the list hierarchy structure.

Output should be like this:

l = [[['da-1.txt', 'it-1.txt'], 'da-2.txt'], ['en-1.txt', 'en-2.txt], 'it-2.txt']

Answer 1

You could go over the list and for each element check if it's a list. If it isn't, replace it with the corresponding element of the dictionary if it exists. If it is, apply the same algorithm recursively:

def rec_replace(l, d):
    for i in range(len(l)):
        if isinstance(l[i], list):
            rec_replace(l[i], d)
        else :
            l[i] = d.get(l[i], l[i])

Note:
This implementation is of an in-place replacement of the list's elements. Alternatively, a similar approach could be used to return a new list instead.