5 examples of 'check if number is power of 2' in Python

109
def is_power2(n):
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    """
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        Check if n is a power of 2
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    """
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    assert isinstance(n, int)
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    return ((n & (n-1)) == 0) and n != 0

24
def is_a_power_of_2(x):
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    return True if x==1 else False if x%2 else is_a_power_of_2(x//2)

37
def isPowerOfTwo(self, n: int) -> bool:
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    return n > 0 and not (n & (n - 1))

2
def isPowerOfTwo(self, n):
3
  """
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  :type n: int
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  :rtype: bool
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  """
7
  return n != 0 and (n & -n) == n

37
def isPowerOfFour(self, n):
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    """
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    :type num: int
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    :rtype: bool
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    """
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    if n < 1:
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        return False
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    while n > 1:
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        if n % 4 != 0:
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            return False
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        n //= 4
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    return True