Python: One-liner to perform an operation upon elements in a 2d array (list of lists)?

Question

I have a list of lists, each containing a different number of strings. I'd like to (efficiently) convert these all to ints, but am feeling kind of dense, since I can't get it to work out for the life of me. I've been trying: newVals = [int(x) for x in [row for rows in values]]

Where 'values' is the list of lists. It keeps saying that x is a list and can therefore not be the argument if int(). Obviously I'm doing something stupid here, what is it? Is there an accepted idiom for this sort of thing?

Answer 1

This leaves the ints nested

[map(int, x) for x in values]

If you want them flattened, that's not hard either

for Python3 map() returns an iterator. You could use

[list(map(int, x)) for x in values]

but you may prefer to use the nested LC's in that case

[[int(y) for y in x] for x in values]

Answer 2

Another workaround

a = [[1, 2, 3], [7, 8, 6]]
list(map(lambda i: list(map(lambda j: j - 1, i)), a))
[[0, 1, 2], [6, 7, 5]] #output