What\'s the Most Efficient Way to Sum the Digits of an Integer?

Sum the Digits of a Number

Question:

Determine the most efficient methods for computing the sum of digits in a given integer.

Answer:

While the provided Pythonic methods involving string conversion and mapping approach (sum(int(digit) for digit in str(number)) and sum(map(int, str(number)))) are acceptable, a more efficient approach exists: direct integer manipulation.

Integer Manipulation Methods:

• sum_digits(): Iterates through each digit by modulo and division operations.
• sum_digits2(): Similar to sum_digits() but using divmod for efficiency.
• sum_digits3(): Streamlines the operations into a single assignment statement.

Performance Comparison:

Benchmarking these methods reveals their relative efficiency:

def sum_digits3(n) is the fastest, followed by sum_digits(), sum_digits2(), sum(map(int, str(n))), sum([int(digit) for digit in str(n)]), 
    and finally sum(int(digit) for digit in str(n)).

Hence, for optimal speed, utilizing direct integer manipulation methods like sum_digits3() is recommended over string-based approaches.

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