9.11.2. Numbers and math#

9.11.2.1. Python arithmetic operators:#

Here is an overview about the basic math operators and how they are used in Python v3. You can type simple math equations (e.g. the examples from the table below) directly into the itom terminal to see how some of the operators work. Alternatively, you can create yourself a new Python script file and type in some math there.

Operator	Description	Example
`+`	Addition	10 + 20 will give 30
`-`	Subtraction	10 - 20 will give -10
`*`	Multiplication	10 * 20 will give 200
`/`	Division	20 / 10 will give 2
`%`	Modulus	20 % 10 will give 0
`**`	Exponent	`10**2` will give `10` to the power `2`
`//`	Floor division	`9//2` is equal to `4` and `9.0//2.0` is equal to `4.0`

9.11.2.2. Python comparison/boolean operators:#

In addition, comparison operators are shown in the following table. As displayed in the example column, they mainly serve for the comparison of two numbers and return a boolean value - true or false.

Operator	Description	Example
`==`	Equal	(10 == 20) is not true
`!=`	Not equal	(10 != 20) is true
`<>`	Not equal	(10 <> 20) is true
`<`	Less-than	(10 < 20) is true
`>`	Greater-than	(10 > 20) is not true
`<=`	Less-than-equal	(10 <= 20) is true
`>=`	Greater-than-equal	(10 >= 20) is not true

9.11.2.3. More examples#

Here are a few more examples to practice for yourself how the different operators work. Type in the following source code in another script file and run the code to see what happens.

# Python calculates with the correct order of operations
print(25 + 30 / 6)
print(100 - 25 * 3 % 4)
print(3 + 2 + 1 - 5 + 4 % 2 - 1 / 4 + 6)

# Difference between regular division (/) and floor division (//)
print(8/5)
print(8//5)

You can also combine your math/arithmetic operations with the print() command

print("Is it true that 3 + 2 < 5 - 7?")     # outputs all characters in between the quotation marks
print(3 + 2 < 5 - 7)                        # prints the actual result

print("Is 5 greater than 7?", 5 > -2)       # combines the previous example in one line

print("What is 3 + 2?", 3 + 2 )

Is it true that 3 + 2 < 5 - 7?
False
Is 5 greater than 7? True
What is 3 + 2? 5

As you might have noticed, lines starting with the hash character # are not interpreted by Python. In this fashion, the programmer can render his file easier understandable for another programmer or for himself when coming back to a complex program after a while. Comments can also start behind a line of code. They extend until the end of the physical line.

Also, you can combine the print() command with mathematic/arithmetic operations, which is explained in more detail in chapter Strings and text.