From a list containing letters and numbers, how do I create a list of the positions of strings that fit a parameter?

Question

I have a list created from a list(input()), that contains letter and numbers, like ['F', 'G', 'H', '1', '5', 'H'] I don't know the contents of the list before hand.

How would I create a new list that shows the positions of strings that fit a predefined parameter so that I could receive an output like number_list = [3, 4] and letter_list = [0, 1, 2, 5]?

I think my answer might involve index, enumerate(), and a for loop but I'm not sure how to go about filtering list contents in the way I want. I want the positional values of the strings in the list so I can use min() and max() functions so that the leftmost letter cant appear after the rightmost number. And later prevent the first number being used from being a 0.

Answer 1

You can use a simple for loop with isdigit():

def _collect(L):
    nums, alphas = [], []
    for i, val in enumerate(L):
        if val.isdigit():
            nums.append(i)
        else:
            alphas.append(i)
    return nums, alphas


print(_collect(['F', 'G', 'H', '1', '5', 'H']))

Prints

([3, 4], [0, 1, 2, 5])