Given a nested list of integers, implement an iterator to flatten it. Each element is either an integer, or a list -- whose elements may also be integers or other lists. For example, if the input is [[1,1],2,[1,1]], then the output is [1, 1, 2, 1, 1]. If the input is [1,[4,[6]]], then the output is [1, 4, 6].

Would anyone be able to advise me as to where the code below went wrong? I am just starting out with python.

def eb34(list1):flat_list = []for i in range(len(list1)):if type(list[i]) == list:flat_list += flatten(list1[i])else:flat_list.append(list1[i])return flat_list

You can use recursion:

def flatten(arg):if not isinstance(arg, list): # if not listreturn [arg]return [x for sub in arg for x in flatten(sub)] # recurse and collectprint(flatten([[1,1],2,[1,1]])) # [1, 1, 2, 1, 1]
print(flatten([1,[4,[6]]]))     # [1, 4, 6]

Or to make a generator,

def flatten(arg):if not isinstance(arg, list): # if not listyield argelse:for sub in arg:yield from flatten(sub)print(*flatten([[1,1],2,[1,1]])) # 1 1 2 1 1
print(*flatten([1,[4,[6]]]))     # 1 4 6