Python list as a list indices

Question

Suppose we have two lists

list_A = [1,3,4,54,3,5,6,2,6,77,73,39]
list_B = [0,3,2,8]

I want to access elements of list_A that have the values in list_B as their indices (without using loops).

After implementing it, the result should be as follows for the above case:

[1, 54, 4, 6]

Is there any easy method to do this without bothering with for loops (calling it explicitly in the code) ?

Answer 1

Everything will use a loop internally*, but it doesn't have to be as complicated as you might think. You can try a list comprehension:

[list_A[i] for i in list_B]

Alternatively, you could use operator.itemgetter:

list(operator.itemgetter(*list_B)(list_A))

---

>>> import operator
>>> list_A = [1,3,4,54,3,5,6,2,6,77,73,39]
>>> list_B = [0,3,2,8]
>>> [list_A[i] for i in list_B]
[1, 54, 4, 6]
>>> list(operator.itemgetter(*list_B)(list_A))
[1, 54, 4, 6]

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* OK! Maybe you don't need a loop with recursion, but I think it's definately overkill for something like this.