question about list comprehension

[adriaanNL]

I am practicing for the python PCAP exam and i don't understand this excercise:

How many empty lines will the following snippet send to the console?

l = [[c for c in range(r)] for r in range(3)]
for x in l:
    if len(x) < 2:
    print()

I do understand easy list comprehensions but not this one with c for c in range®.

If someone could explain this I would be very thankful.

[buran]

it is list comprehension inside list comprehension. the result will be list of lists