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In every programming language, including Python, operations don’t just happen haphazardly. There’s a specific order to how calculations and evaluations occur, governed by a concept called “operator precedence”. This article illuminates the rules of operator precedence in Python, ensuring your expressions always evaluate as intended.
Understanding Operator Precedence in Python
Operator precedence, often likened to the arithmetic “order of operations” from math classes, defines the sequence in which operations are performed in a complex expression.
Example:
result = 3 + 4 * 2
In the above code, multiplication has a higher precedence than addition, so 4 * 2 is evaluated first, followed by the addition, making result 11, not 14.
Python Operator Hierarchy
To avoid confusion, it’s crucial to know the hierarchy of operations in Python. Here’s a simplified order:
- Parentheses
() - Exponentiation
** - Unary minus
- - Multiplication
*, Division/, and Modulus% - Addition
+and Subtraction-
It’s worth noting that operators with the same precedence level are evaluated from left to right.
Example:
result = 15 - 3 + 2
Here, subtraction and addition have the same precedence. Thus, the expression is evaluated left-to-right, and result will be 14.
Order of Operations in Python: Advanced Operators
Beyond basic arithmetic, Python supports a plethora of operators like bitwise, logical, and comparison operators. Each has its position in the precedence hierarchy.
For instance, logical operators (and, or, not) have lower precedence than comparison operators (<, >, ==, !=).
Example:
outcome = 5 < 8 and 7 > 10
In this example, both comparison operations are evaluated before the and operation.
Tips for Navigating Python Arithmetic Priority
- Use Parentheses Liberally: If unsure about precedence, use parentheses to group operations. It makes code clearer.
- Consult the Python Documentation: The official Python docs provide a detailed table of operator precedence.
- Practice: The more you code, the more intuitive these rules become.
Conclusion
Understanding operator precedence in Python is crucial for writing effective, error-free code. By familiarizing yourself with the rules and hierarchies of operations, you can ensure that your Python programs run as expected.
by the Bito team. 
