How Can I Efficiently Check if a String Represents an Unsigned Integer in Python?

Checking If a String Represents a Number (Unsigned Integer on Non-Negative Integers)

In Python, one can determine if a string represents an integer or float using the float() function. However, this method can be cumbersome.

For instance, the following code checks if a string is numeric:

def is_number(s):
    try:
        float(s)
        return True
    except ValueError:
        return False

However, there's a more efficient approach for non-negative (unsigned) integers.

Using isdigit()

The isdigit() method can be used to verify if a string consists exclusively of digits. It is suitable for unsigned integers (non-negative whole numbers).

a = "03523"
print(a.isdigit())  # Output: True

b = "963spam"
print(b.isdigit())  # Output: False

This approach is more efficient for unsigned integers because it avoids the potentially expensive overhead of conversion.

Note that for Python 2 Unicode strings, the isnumeric() method serves a similar function.

Additional Resources

• [isdigit()], Python2 documentation: https://docs.python.org/2/library/stdtypes.html#str.isdigit
• [isdigit()], Python3 documentation: https://docs.python.org/3/library/stdtypes.html#str.isdigit
• [isnumeric()] for Python 2 Unicode strings: https://docs.python.org/2/library/stdtypes.html#str.isnumeric

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