i have a rule of thumb around “one liner” [0] comprehensions that go beyond two nested for loops and/or multiple if conditions — turn it into a generator functi

i have a rule of thumb around “one liner” [0] comprehensions that go beyond two nested for loops and/or multiple if conditions — turn it into a generator function def gen_not_one_y_from_xs(xs): for ys in xs: for y in ys: if y != 1: yield y # … later, actual call not_one_ys = list(gen_y_from_xs(my_xs)) the point of the rule being — if there are two nested for loops in a comprehension then it’s more complicated than previously thought and should be written out explicitly. list comprehensions are a convenience shortcut, so treat them as such and only use them for simple/obvious loops, basically. edit — also, now it’s possible to unit test the for loop logic and debug each step, which you cannot do with a list comprehension (unless a function is just returning the result of a list comprehension… which is… yeah… i mean you could do that…) [0]: 9 times out of 10, multiple for loop comprehensions are not one liners and end up sprawling over multiple lines and become an abject misery to debug.