Question

What would be the most efficient\elegant way in Python to find the index of the first non-empty item in a list?

For example, with

list_ = [None,[],None,[1,2],'StackOverflow',[]]

the correct non-empty index should be:

3

Answer 1

>>> lst = [None,[],None,[1,2],'StackOverflow',[]]
>>> next(i for i, j in enumerate(lst) if j)
3

if you don’t want to raise a StopIteration error, just provide default value to the next function:

>>> next((i for i, j in enumerate(lst) if j == 2), 42)
42

P.S. don’t use list as a variable name, it shadows built-in.