Python all items in list of lists true

Question

Made a table of True & False, and all I'd like to do is check if they are all True. Used all() successfully before, but for some reason with the below I fail miserably.

data = [[False, False, False], 
[False, False, False], 
[True, True, True], 
[True, True, True]]

print(all(data))
>>> True

Why is this happening?

Answer 1

all does not check the bools in each sublist. Each of the non-empty lists are all truthy.

To check that all the items in all sublists are True , you should do:

all(x for lst in data for x in lst) # -> False

Answer 2

You can pass each sublist to the all function within all using a generator:

print(all(all(i) for i in data))

Output:

False