How to flaten a list of lists in python using a recursive function ?

Question

Hey guys, so i was reading a book about python and in some part of it, there was this fact that you can use a recursive function to flaten a list like A=[1,2,[3,4],[5,[6,7],8],[9],10] into A=[1,2,3,4,5,6,7,8,9,10]. Now i know there are many other ways to flaten a list like using pre-made modules and stuff but my question is about doing it with a recursive function. Thank you all :)

Answer 1

One way to do this

def flat(lis,newlist):
for i in lis:
if isinstance(i,list):
flat(i,newlist)
else:
newlist.append(i)
return newlist

print(flat([1,2,3,[4,5],[6,7]],[]))

isinstance function checks if any item in original list is an instance of class List,if yes it calls the function with an argument being that item otherwise it appends the item to a newlist and returns it at the end of for loop

Answer 2

Thanks guys, they were all useful ^^ cheers