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pow Example, Power Operator
Dot Net Perls
Pow. In exponentiation, one number is multiplied by itself. This is performed with the pow method, a built-in. With two stars, we can also take exponents.
Number
In Python, two stars and pow are equivalent. So we can use whichever one seems clearest. I feel pow is clearer, but I rarely need exponents in programs.
First example. Here we use pow and the exponent operator. We see that 2 squared is 4 (because 2 times 2 is four). You should know this from math class.
Here We use both the two-star operator and the pow method. We see the results of both syntax forms are equal.
# Two squared is four. # ... These syntax forms are identical. print(2 ** 2) print(pow(2, 2)) # Two cubed is eight. print(2 ** 3) print(pow(2, 3))
4 4 8 8
3 arguments. Pow can be used with 3 arguments. The third argument is for modulo division. The result of the exponentiation operation is divided by that number. The remainder is returned.
Here We take the square of 3 to get 9. And then we divide nine by five, so we have a remainder of 4.
Note This version of pow may improve performance. But I have never needed this in a real Python program.
# Compute 3 squared. # ... This is 9. # ... Perform 9 modulo 5 to get result of 4. result = pow(3, 2, 5) print(result)
4
A main goal of Python is syntax clarity. Python programs are easy to read and to write. With pow, we have a choice of syntax to use.
For developers who use many exponentiation operations, two stars might be clearer. But pow is often a less-common operation. For this reason it is probably a better choice overall.
Dot Net Perls is a collection of tested code examples. Pages are continually updated to stay current, with code correctness a top priority.
Sam Allen is passionate about computer languages. In the past, his work has been recommended by Apple and Microsoft and he has studied computers at a selective university in the United States.