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Python pow() Function

The pow() method computes the power of a number by raising the first argument to the second argument.

Syntax​

pow(number, power, modulus)

pow() Parameters​

Python pow() function parameters:

ParameterConditionDescription
numberRequiredThe base value that is raised to a certain power
powerRequiredThe exponent value that raises number
modulusOptionalDivides the result of number paused to a power and finds the remainder: number^power% modulus

pow() Return Value​

Python pow() function returns:

  • number^powerfor number raised to a certain power
  • number^power % modulus if the optional modulus argument is specified
  • 1 if the value of power is 0
  • 0 if the value of number is 0
note

If the exponent (second argument) is negative, then the pow() function returns a float result.

Examples​

Example 1: Calculate Power of a Number​

If two arguments are specified, the pow(x, y) method returns x to the power of y.

x = pow(5, 2)
print(x)    # Output: 25

output

25

Example 1: Calculate Power of a Negative Number​

x = pow(-2, 3)
print(x)    # Output: -8

output

-8

Example 2: Calculate Power of a Float Number​

x = pow(2.5, 2)
print(x)    # Output: 25

output

Example 3: Calculate Power of a Complex Number​

x = pow(3+4j, 2)
print(x)    # Output: (-7+24j)

output

(-7+24j)

Example 4: Calculate Power of a Number and Negative Exponent​

x = pow(2, -2)
print(x)    # Output: 0.25

output

0.25

Example 5: Use ** power operator to compute the Power of a Number​

x = 10**2
print(x)    # Output 100

output

100

Example 6: Calculate Power of a Number using Modulus​

If all the three arguments are specified, pow(x, y, z) function returns x to the power of y, modulus z.

x = pow(5, 2, 3)
print(x)    # Output: 1

output

1

You can achieve the same result using the power operator ** and modulus operator %:

x = 5**2%3
print(x)    # Output: 1

output

1

Example 7: Calculate the Modular Inverse with pow() function​

In modular arithmetic, the modular inverse of a number a modulo m is a number b such that (a * b) % m = 1. This means that b is the multiplicative inverse of a under modulo m.

The modular inverse exists only if a and m are coprime (i.e., their greatest common divisor is 1).

Starting with Python 3.8, the pow() function can directly calculate the modular inverse when provided with a negative exponent because raising a number to a negative power is equivalent to finding its multiplicative inverse modulo m.

For example, let's calculate the modular inverse of 38 modulo 97. The result is 23, which verifies that (38 * 23) % 97 = 1.

# Only Python  3.8 and later
result = pow(38, -1,  97)
print(result)  # Output:  23

output

23

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