Python Exponent – 4 Operators Every Coder Must Know

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Python has four ways to calculate the n-th power (exponent) of x so that xⁿ=x*x*...*x that multiplies the base x with itself, and repeating this n-times.

  • Method 1: Use the double-asterisk operator such as in x**n.
  • Method 2: Use the built-in pow() function such as in pow(x, n).
  • Method 3: Import the math library and calculate math.pow(x, n).
  • Method 4: Import the NumPy library and calculate np.power(x, n).

Let’s dive into these four methods one by one!

Python Exponent – 4 Operators Every Coder Must Know

Method 1: Double-Asterisk x**n

The double asterisk (**) symbol is used as an exponentiation operator. The left operand is the base and the right operand is the power. For example, the expression x**n multiplies the value x with itself, n times.

Let’s have a look at a couple of simple examples:

>>> 2**2
4
>>> 2**3
8
>>> 2**4
16
>>> 2**5
32
>>> -3**3
-27

You can also raise to a negative power in which case, the whole expression is inverted such that x**-n == 1/(x**n).

>>> 2**-3
0.125
>>> 2**-2
0.25

Method 2: Built-In pow(x, n)

For pow(x, y), the pow() function returns the value of x raised to the power y. It performs the same function as the power operator ** , i.e. x**y, but differs in that it comes with an optional argument called mod.

ParameterDescription
expA number that represents the base of the function, whose power is to be calculated.
baseA number that represents the exponent of the function, to which the base will be raised.
modA number with which the modulo will be computed.

Here are a couple of examples without the mod argument:

>>> pow(5, 2)
25
>>> pow(-3, 3)
-27
>>> pow(2, -2)
0.25

If we have a mod argument such as z in pow(x, y, z), the function first performs the task of raising x to the power y and then that result is used to perform the modulo task with respect to z. It would be the equivalent of (x**y) % z .

Here are three examples with the mod argument:

>>> pow(14, 7, 5)
4
>>> pow(-8, 3, 5)
3
>>> pow(2, 4, -3)
-2

Method 3: math.pow(x, n)

The math.pow(x, n) function raises x to the power of n. It calculates the exponent function. The difference to the built-in pow() function is that it doesn’t allow the optional mod argument and it always returns a float, even if the input arguments are integers.

Consider the following examples that show how to use it with integer arguments, float arguments, negative bases, and negative exponents:

>>> math.pow(2, 3)
8.0
>>> math.pow(2.3, 3.2)
14.372392707920499
>>> math.pow(-2, 3)
-8.0
>>> math.pow(2, -3)
0.125

Method 4: numpy.power(x, n)

The NumPy library has a np.power(x, n) function that raises x to the power of n. While the inputs can be arrays, when used on numerical values such as integers and floats, the function also works in the one-dimensional case.

>>> np.power(2, 2)
4
>>> np.power(2, 3)
8
>>> np.power(-2, 3)
-8
>>> np.power(2.0, -3)
0.125

However, if you try to raise an integer to a negative power, NumPy raises an error:

>>> np.power(2, -3)
Traceback (most recent call last):
  File "<pyshell#25>", line 1, in <module>
    np.power(2, -3)
ValueError: Integers to negative integer powers are not allowed.

To fix it, convert the first integer argument to a float value, for example using the float() function.

Summary

You’ve learned four ways to calculate the exponent function in Python.

Method 1: Use the double-asterisk operator such as in x**n.

Method 2: Use the built-in pow() function such as in pow(x, n).

Method 3: Import the math library and calculate math.pow(x, n).

Method 4: Import the NumPy library and calculate np.power(x, n).

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Arithmetic Operators

Arithmetic operators are syntactical shortcuts to perform basic mathematical operations on numbers.

OperatorNameDescriptionExample
+AdditionCalculating the sum of the two operands3 + 4 == 7
--SubtractionSubtracting the second operand from the first operand4 - 3 == 1
*MultiplicationMultiplying the first with the second operand3 * 4 == 12
/DivisionDividing the first by the second operand3 / 4 == 0.75
%ModuloCalculating the remainder when dividing the first by the second operand7 % 4 == 3
//Integer Division, Floor DivisionDividing the first operand by the second operand and rounding the result down to the next integer8 // 3 == 2
**ExponentRaising the first operand to the power of the second operand2 ** 3 == 8