# [Tutor] "Strange" behaviour of list comprehension

Wed Feb 13 14:45:09 CET 2013

```I'm playing around with list comprehension and in IDLE typed this in.  I actually wanted it to return all tuples satisfying the condition where z is the sum of x and y. I kind of got mixed up with the syntax, hence I put a comma in there instead of an "if".  I'd like some assistance understanding what it's doing...
Thanks!

>>> somelist = [(x,y,z) for x in range(1,10) for y in range(x,10) for z in range(y,10), x+y==z]
>>> somelist
[(1, 1, [1, 2, 3, 4, 5, 6, 7, 8, 9]), (1, 1, False), (1, 2, [2, 3, 4, 5, 6, 7, 8, 9]), (1, 2, False), (1, 3, [3, 4, 5, 6, 7, 8, 9]), (1, 3, False), (1, 4, [4, 5, 6, 7, 8, 9]), (1, 4, False), (1, 5, [5, 6, 7, 8, 9]), (1, 5, False), (1, 6, [6, 7, 8, 9]), (1, 6, False), (1, 7, [7, 8, 9]), (1, 7, False), (1, 8, [8, 9]), (1, 8, False), (1, 9, [9]), (1, 9, False), (2, 2, [2, 3, 4, 5, 6, 7, 8, 9]), (2, 2, False), (2, 3, [3, 4, 5, 6, 7, 8, 9]), (2, 3, False), (2, 4, [4, 5, 6, 7, 8, 9]), (2, 4, False), (2, 5, [5, 6, 7, 8, 9]), (2, 5, False), (2, 6, [6, 7, 8, 9]), (2, 6, False), (2, 7, [7, 8, 9]), (2, 7, False), (2, 8, [8, 9]), (2, 8, False), (2, 9, [9]), (2, 9, False), (3, 3, [3, 4, 5, 6, 7, 8, 9]), (3, 3, False), (3, 4, [4, 5, 6, 7, 8, 9]), (3, 4, False), (3, 5, [5, 6, 7, 8, 9]), (3, 5, False), (3, 6, [6, 7, 8, 9]), (3, 6, False), (3, 7, [7, 8, 9]), (3, 7, False), (3, 8, [8, 9]), (3, 8, False), (3, 9, [9]), (3, 9, False), (4, 4, [4, 5, 6, 7, 8, 9]), (4, 4, False), (4, 5, [5, 6, 7, 8, 9]), (4, 5, False), (4, 6, [6, 7, 8, 9]), (4, 6, False), (4, 7, [7, 8, 9]), (4, 7, False), (4, 8, [8, 9]), (4, 8, False), (4, 9, [9]), (4, 9, False), (5, 5, [5, 6, 7, 8, 9]), (5, 5, False), (5, 6, [6, 7, 8, 9]), (5, 6, False), (5, 7, [7, 8, 9]), (5, 7, False), (5, 8, [8, 9]), (5, 8, False), (5, 9, [9]), (5, 9, False), (6, 6, [6, 7, 8, 9]), (6, 6, False), (6, 7, [7, 8, 9]), (6, 7, False), (6, 8, [8, 9]), (6, 8, False), (6, 9, [9]), (6, 9, False), (7, 7, [7, 8, 9]), (7, 7, False), (7, 8, [8, 9]), (7, 8, False), (7, 9, [9]), (7, 9, False), (8, 8, [8, 9]), (8, 8, False), (8, 9, [9]), (8, 9, False), (9, 9, [9]), (9, 9, False)]
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