What are operators in Python?
Typically, math involves about four core operations: addition, subtraction, multiplication, and division. Python supports these four operators and a few others. Let's explore the most common operators you'll use in your programs.
Addition
Python uses + to indicate addition. Using + between two numbers adds them together and provides the total.
answer = 30 + 12
print(answer)
Output: 42
Note
Operators behave the same when using literal numbers (such as 42) or variables.
Subtraction
Similarly, Python uses - for subtraction. Using - between two numbers subtracts the two numbers and provides the difference.
difference = 30 - 12
print(difference)
Output: 18
Multiplication
In Python, * is the multiplication operator. It provides the product of two numbers:
product = 30 * 12
print(product)
Output: 360
Division
Finally, / is used for division. It provides the quotient of two numbers:
quotient = 30 / 12
print(quotient)
Output: 2.5
Work with division
Imagine you need to convert a number of seconds into minutes and seconds for display.
seconds = 1042
The first step is to determine the number of minutes in 1042 seconds. With 60 seconds in a minute, you can divide by 60 and get an answer of 17.3666667. The number you're interested in is simply 17. You always want to round down, by using what's known as floor division. To perform floor division in Python, you use //.
seconds = 1042
display_minutes = 1042 // 60
print(display_minutes)
Output: 17
The next step is to determine the number of seconds. This number is the remainder of 1042 if you divide by 60. You can find the remainder by using the modulo operator, which is % in Python. The remainder of 1042 / 60 is 22, which is what the modulo operator will provide.
seconds = 1042
display_minutes = 1042 // 60
display_seconds = 1042 % 60
print(display_minutes)
print(display_seconds)
17
22
Order of operation
Python honors the order of operation for math. The order of operation dictates that expressions should be evaluated in the following order:
- Parentheses
- Exponents
- Multiplication and division
- Addition and subtraction
Notice how parentheses are evaluated before any other operations. Using parentheses allows you to ensure code is run in a predictable manner, and your code becomes easier to read and maintain. As a result, it's a best practice to use parentheses even if order of operation would evaluate the same way without them. In the following two lines of code, the second one is more understandable because the parentheses give a clear indication of what operation will be performed first.
result_1 = 1032 + 26 * 2
print(result_1)
result_2 = 1032 + (26 * 2)
print(result_2)
The answer is the same in both cases - 1084.