在Python中展平列表（任意深度）

Posted 2021-02-23

Flatten a list of lists (or tuple of tuples, list of tuples, etc.) to any depth of nesting using no mutable objects.

def flat(lst):
	'''
	return a tuple making from all values from the flatten list of lists (or tuple of tuples, etc.)
	'''
	return reduce(lambda l, e: (isinstance(e, list) or isinstance(e, tuple)) and l + flat(e) or l + (e,), lst, ())
 
assert flat([]) == ()
assert flat((1,)) == (1,)	
assert flat([1, 2, 3]) == (1, 2, 3)
assert flat([(1,2),[3,4,[5,6]],7,8,(9,(0,))]) == (1, 2, 3, 4, 5, 6, 7, 8, 9, 0)