通过递归查找列表深度时出现全局变量问题

Question

I have a recursion function with a global variable for checking list depth, it works correct until you start it double or more times because variable doesn't reset. I've already seen the simplest way, but can I repair my code for correct work or it's just piece of dead code? Oh, I really have troubles with recursion..

depth = 1
def list_depth(arr):
    global depth
    for element in arr:
        # print(type(element))
        if type(element) == list:
            depth += 1
            list_depth(element)
        else:
            continue
        return depth
    return depth

print(list_depth([1, [2, [3, [4, [5, [6], 5], 4], 3], 2], 1])) # => 6 correct
print(list_depth([1, [2, [3, [4, [5, [6], 5], 4], 3], 2], 1])) # => 11 wrong

Answer 1

there are a few ways you could go about it... if you really want to keep your code as it is you'll have to reset depth before each call like this:

print(list_depth([1, [2, [3, [4, [5, [6], 5], 4], 3], 2], 1]))
depth=1
print(list_depth([1, [2, [3, [4, [5, [6], 5], 4], 3], 2], 1]))

output:

6
6

but a better solution could be sending depth as one of the function arguments instead of declaring it as a global argument

this should do the trick:

def list_depth(arr,depth=1):
    for element in arr:
        # print(type(element))
        if type(element) == list:
            depth += 1
            return list_depth(element,depth)
        else:
            continue
    return depth

print(list_depth([1, [2, [3, [4, [5, [6], 5], 4], 3], 2], 1])) 
print(list_depth([1, [2, [3, [4, [5, [6], 5], 4], 3], 2], 1]))

output:

6
6