How to know if a list is filled with a same number in Python 3?

Question

I manipulating big list in my program, so what's the fastest way to know if a list is filled with a same number ? And I'm not able to use module.

As example :

>>> isFilled([1,1,1,1,1])
True
>>> isFilled([5,5,5,5])
True
>>> isFilled([1,6,5,1,1])
False

I have done this, but it's create a new list and that's a problem as I manipulating big list :

def isFilled(lst):
    return [lst[0]]*len(lst) in lst

Answer 1

Here: all(x==lst[0] for x in lst). (x==lst[0] for x in lst) is a generator comprehension. all() returns True if all the elements of an iterator (a generator comprehension is an iterator) return True when passed to bool(), which converts a value into a boolean value (True or False). Note that it evaluates as False immediately after a different element is spotted.