how to convert selected string in list to integer python

Question

this question is to convert selected strings in the list into integers.

However, this code converts the whole list into integer. how can i fix this?

list = [['x', 'x', '1', 'x'], ['4', 'x', 'x', 'x'], ['x', 'x', 'x', '2'], ['x', '3', 'x', 'x']]

def convert(str_list):
for i in range(len(str_list)):
    for j in range(len(str_list)):
        if str_list[i][j].isdigit():
            str_list[i][j] = int(str_list[i][j])
return(str_list)

edit: this code ^above also works. i edited it already!! The output should be

[['x', 'x', 1, 'x'], [4, 'x', 'x', 'x'], ['x', 'x', 'x', 2], ['x', 3, 'x', 'x']]

Answer 1

map this function to your list:

def str2num(s):
# Convert a string to an int, float, or stripped string

    try:
        return int(s)

    except ValueError:
        try:
            return float(s)

        except ValueError:
            return s.strip()

Answer 2

You can check if a string contains digits with .isdigit() . So you can call int only if the element at that index contains digits:

def convert(str_list):
    n = 0
    while n < len(str_list):
        if str_list[n].isdigit():
            str_list[n] = int(str_list[n])
        n += 1
    return(str_list)

You can then loop over all lists in your main list and convert them individually:

lst = [['x', 'x', '1', 'x'], ['4', 'x', 'x', 'x'], ['x', 'x', 'x', '2'], ['x', '3', 'x', 'x']]
for l in lst:
    convert(l)

print(lst)

Output

[['x', 'x', 1, 'x'], [4, 'x', 'x', 'x'], ['x', 'x', 'x', 2], ['x', 3, 'x', 'x']]

Answer 3

A list comprehension would be perfect for this, (also don't overwrite builtins!)

data = [['x', 'x', '1', 'x'], ['4', 'x', 'x', 'x'], ['x', 'x', 'x', '2'], ['x', '3', 'x', 'x']]

def converted(str_list):
    return [int(s) if s.isdigit() else s for s in data]

If you must use a while loop you can do this:

def convert(str_list):
    for i in range(len(data)):
        for n in range(len(data[i])):
            try: data[i][n] = int(data[i][n])
            except: pass