Operators

Operators are used to perform various operations on variables and values. The standard arithmetic and assignment operators are the most familiar.

Syntax

The following code snippet uses the assignment operator, =, to set my_variable to the value of num1 and num2 with an arithmetic operator acting on them. For example, if operator represented *, my_variable would be assigned a value of num1 * num2.

my_variable = num1 operator num2

Python operators can be organized into the following groups:

• Arithmetic operators for performing traditional math evaluations.
• Assignment operators for assigning values to variables.
• Comparison operators for comparing two values.
• Logical operators for combining boolean values.

Arithmetic Operators

Python has the following arithmetic operators:

• Addition, +, which returns the sum of two numbers.
• Subtraction, -, which returns the difference of two numbers.
• Multiplication, *, which returns the product of two numbers.
• Division, /, which returns the quotient of two numbers.
• Exponentiation, **, which returns the value of one number raised to the power of another.
• Modulus, %, which returns the remainder of one number divided by another.
• Floor division, //, which returns the integer quotient of two numbers.

Assignment Operators

Python includes the following assignment operators:

• The = operator assigns the value on the right to the variable on the left.
• The += operator updates a variable by incrementing its value and reassigning it.
• The -= operator updates a variable by decrementing its value and reassigning it.
• The *= operator updates a variable by multiplying its value and reassigning it.
• The /= operator updates a variable by dividing its value and reassigning it.
• The %= operator updates a variable by calculating its modulus against another value and reassigning it.

Comparison Operators

Python has the following comparison operators:

• Equal, ==, for returning True if two values are equal.
• Not equal, !=, for returning True if two values are not equal.
• Less than, <, for returning True if left value less than right value.
• Less than or equal to, <=, for returning True if left value is less than or equal to right value.
• Greater than, >, for returning True if left value greater than right value.
• Greater than or equal to, >=, for returning True if left value greater than or equal to right value.

Logical Operators

Python has the following logical operators:

• The and operator returns True if both statements are True.
• The or operator returns True if either statement is True.
• The not operator returns True if its associated statement is False.

Order of Operations

Python evaluates an expression in order of precedence as follows:

• Items in parentheses, ((…)), have the highest level of precedence, expressions within them are evaluated first.
• Exponentiation (**)
• Multiplication and division operators (*, /, // & %)
• Addition and subtraction (+ & -)
• Comparison (<, <=, > & >=)
• Equality (== & !=)
• not
• and
• or

Membership operators

• The in operator returns True if the element on the left is found within the iterable object on the right. Here, the element on the right side of the in operator must be an iterable object like a list, string, dictionary, etc.
• The not in operator returns True if the element on the left is not found within the iterable object on the right. Again, the element on the right side of the not in operator must be an iterable object.

Note: Items at the same precedence are evaluated left to right. The exception to this is exponentiation, which evaluates right to left.