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b3b89d9460
This is a documentation fix. This fix patches a mistake in the description of the Armstrong number. * * Doc fix * Armstrong number is not the sum of cube's of number digits, but the sum of number's digits each raised to the power of the number of digits * Update armstrong_numbers.py Line shorten
71 lines
1.9 KiB
Python
71 lines
1.9 KiB
Python
"""
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An Armstrong number is equal to the sum of its own digits each raised
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to the power of the number of digits.
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For example, 370 is an Armstrong number because 3*3*3 + 7*7*7 + 0*0*0 = 370.
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An Armstrong number is often called Narcissistic number.
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"""
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def armstrong_number(n: int) -> bool:
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"""
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Return True if n is an Armstrong number or False if it is not.
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>>> armstrong_number(153)
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True
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>>> armstrong_number(200)
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False
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>>> armstrong_number(1634)
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True
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>>> armstrong_number(0)
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False
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>>> armstrong_number(-1)
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False
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>>> armstrong_number(1.2)
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False
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"""
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if not isinstance(n, int) or n < 1:
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return False
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# Initialization of sum and number of digits.
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sum = 0
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number_of_digits = 0
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temp = n
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# Calculation of digits of the number
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while temp > 0:
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number_of_digits += 1
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temp //= 10
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# Dividing number into separate digits and find Armstrong number
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temp = n
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while temp > 0:
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rem = temp % 10
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sum += rem ** number_of_digits
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temp //= 10
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return n == sum
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def narcissistic_number(n: int) -> bool:
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"""Return True if n is a narcissistic number or False if it is not"""
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expo = len(str(n)) # power, all number will be raised to
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# each digit will be multiplied expo times
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temp = [(int(i) ** expo) for i in str(n)]
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# check if sum of cube of each digit is equal to number
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return n == sum(temp)
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def main():
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"""
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Request that user input an integer and tell them if it is Armstrong number.
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"""
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num = int(input("Enter an integer to see if it is an Armstrong number: ").strip())
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print(f"{num} is {'' if armstrong_number(num) else 'not '}an Armstrong number.")
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print(f"{num} is {'' if narcissistic_number(num) else 'not '}an Armstrong number.")
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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main()
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