Question

In Python, I have a list of lists like the following:

[[1,2,3, 'L'], ['L'], [1]]

and I want to compute for each sublist the average over all the numerical elements. Values ‘L’ should thus be excluded. The result for the above example should be:

[2, [], 1]

Is there any quick way of doing this in one line?

Thanks.

Answer 1

Here’s a highly unreadable one-liner, assuming you’ve already imported numpy and numbers. Lists with no numeric elements show up as nan in the resulting list.

[numpy.mean([x for x in sublist if isinstance(x, numbers.Number)]) for sublist in mainlist]