is perfect square

How do you write a program that checks if a number is perfect square or not.

def isPerfectSquare(x):
    i = 0
    while i * i < x:
        i += 1
    return i * i == x

This is such a beautiful code.

Is it??? How about this.

def isPerfectSquare(x):
    xRoot = int(x ** 0.5 + 0.1)
    return xRoot * xRoot == x

or in my favourite lambda way,

isPerfectSquare = lambda x: int(x ** 0.5 + 0.1) ** 2 == x

If you know what is going on, you'll love the recipe. If you don't then start thinking.