Python Operators
In this page:
Arithmetic Operators: Doing Math
Arithmetic operators -- +, -, *, /, // (floor division), % (modulo), and ** (exponentiation) -- perform mathematical calculations on numbers, and (for + specifically) also work on strings and lists to mean concatenation or repetition instead of addition.
Note: Remember that / always produces a float result in Python 3, even when dividing two integers evenly -- use // specifically when you need an integer (floor-divided) result.
Warning: Confusing / (true division, always returns a float) with // (floor division, rounds down to an integer) is a common source of unexpected float results.
Example: Arithmetic Operators: Doing Math
print(7 + 3, 7 - 3, 7 * 3, 7 / 3, 7 // 3, 7 % 3, 7 ** 2)Comparison Operators: Testing Relationships
Comparison operators -- ==, !=, <, >, <=, >= -- compare two values and always produce a boolean result (True or False), forming the building blocks of every condition used in an if statement or a while loop.
Note: Use == for comparing values, reserving a single = strictly for assignment -- mixing these up is one of the most common syntax mistakes for beginners coming from other contexts.
Warning: Comparing values of very different, incompatible types (like a string and an integer) with < or > raises a TypeError in Python 3, unlike some looser languages.
Example: Comparison Operators: Testing Relationships
print(5 == 5, 5 != 3, 5 > 3, 5 < 3)Logical Operators: Combining Conditions
Logical operators -- and, or, not -- combine multiple boolean expressions into one overall result. and requires both sides to be True, or requires at least one side to be True, and not simply inverts a single boolean value.
Note: Use parentheses to group parts of a complex logical expression explicitly, even when not strictly required, to make the intended logic obvious to a reader.
Warning: Python short-circuits and/or -- if the left side of and is False, the right side is never evaluated at all, which matters if that right side has a side effect like calling a function.
Example: Logical Operators: Combining Conditions
a, b = True, False
print(a and b, a or b, not a)Assignment Operators: Storing and Updating Values
Beyond the basic = for assigning a value, Python offers compound assignment operators -- +=, -=, *=, /=, and more -- that update a variable based on its own current value in one concise step, like count += 1 to increment a counter.
Note: Use compound assignment (like total += price) whenever updating a variable based on its own current value, since it is both more concise and clearer in intent than the fully spelled-out version.
Warning: total += price is exactly equivalent to total = total + price -- forgetting this equivalence can make the compound form feel more mysterious than it actually is.
Example: Assignment Operators: Storing and Updating Values
total = 10
total += 5
print(total)Specialized Families: Identity, Membership, and Bitwise
Beyond the everyday operator families, Python has three more specialized ones: identity operators (is, is not) check whether two variables reference the exact same object; membership operators (in, not in) check whether a value exists within a collection; and bitwise operators (&, |, ^, ~, <<, >>) manipulate individual bits of integers directly.
Note: Use == to compare VALUES for equality, and reserve is specifically for checking whether two variables refer to the literal same object in memory -- these answer genuinely different questions.
Warning: Confusing == (value equality) with is (identity/same-object check) is a subtle but real source of bugs, especially with mutable objects like lists.
Example: Specialized Families: Identity, Membership, and Bitwise
x = [1, 2]
y = x
print(x is y)
print(1 in x)
print(2 & 3)- Confusing = (assignment) with == (comparison) -- a single = sets a variable's value, while == checks whether two values are equal, and mixing them up is one of the most common beginner errors.
- Assuming every operator family behaves the same way across different data types -- + means addition for numbers but concatenation for strings, and understanding this context-dependence matters.
- Forgetting operator precedence and assuming operators are evaluated strictly left to right -- multiplication happens before addition, for instance, unless parentheses say otherwise.
- Python groups operators into families: arithmetic (math), comparison (relationships), logical (combining conditions), assignment (storing values), identity, membership, and bitwise.
- Each operator family solves a different kind of problem -- arithmetic computes values, comparison and logical operators produce True/False results used in conditions.
- Operator precedence determines the order operators are evaluated in a single expression, similar to order of operations in mathematics.
All operator families described here are part of core Python syntax, supported identically in every Python 3 version.
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- Python print()
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- Python Format Strings
- Python f-strings
- Python String Formatting
- Python Arithmetic Operators
- Python Relational Operators
- Python Logical Operators
- Python Bitwise Operators
- Python Assignment Operators
- Python Increment & Decrement
- Python Ternary Operator
- Python Operator Precedence
- Python Identity Operators
- Python Membership Operators
- Python Operators