how to return the order index of each element of a list? [duplicate]

Question

I have a list of Numbers, say L=[50, 10, 30], and in Python I want to return a list giving the order index of each element in L, which would be this output: [2, 0, 1].

Though it seems to be a simple task, many questions on this site (here here and here for instance) focus on the other way round, meaning the index from the sorted list point of view: [1, 2, 0], which is not what I want.

Thanks,

EDIT: about repetitions, i'd like them to be counted as well (draws taken in order of appearance). [50,30,10,30] would give [3,1,0,2]

Answer 1

One liner:

l = [50, 30, 10, 30]
numpy.argsort(numpy.argsort(l))
# array([3, 1, 0, 2])

Answer 2

it is the index list of the sorted order:

def sort_order(lst):
    orders = sorted(list(range(len(lst))), key=lambda x: lst[x])
    ret = [0] * len(lst)
    for i in range(len(ret)):
        ret[orders[i]] = i
    return ret

print(sort_order([50, 10, 30]) # [2,0,1]