Python：存在多个列表时打印非空列表

Question

So let's say I have 10 lists named aj:

I can check which list is empty

if a.empty:

do something

But in what way can I print only the non empty lists:

for all lists in aj: print(non-empty lists)

Answer 1

try list comprehensions:

>>> list_of_lists = [[], [1], [], [2,3],[]]
>>> list_of_lists
[[], [1], [], [2, 3], []]
>>> [ l for l in list_of_lists if l]
[[1], [2, 3]]

because and empty list is not truthy , if l evaluates to false when the list is empty, so it is not witheld.

Answer 2

have you tried just check for any element in the list?

for list_i in all_lists:
  if list_i:
    print(list_i)

Answer 3

let's suppose that you regrouped your 10 lists in a list L so L is now a list of your 10 lists,so this sample of code print the non empty lists which means those who have more than one element: for l in L: if (len(l)>0): print(l)