This is the seventh blog on Python for fintch professionals.
Understanding Operators, Expressions, and Variables in Python
Understanding the core concepts of operators, expressions, and variables is essential for effective coding. These elements form the foundation of how we manipulate data and perform computations in Python. In this post, we’ll explore what operators and expressions are, discuss the basic operators in Python, and delve into how variables work.
What Are Operators and Expressions?
An operator is a symbol that performs operations on one or more values. In contrast, an expression is a combination of values and operators that computes a result. For example, in the expression 1 + 2, the + symbol is the operator, and the entire expression evaluates to 3.
Basic Operators in Python
Python provides several basic operators, each serving a specific purpose. Here are some of the most commonly used ones:
1. Exponentiation (**): This operator raises a number to the power of another. For example, 2 ** 3 computes 2 to the power of 3 , which equals 8.
2. Multiplication (*): This operator multiplies two numbers. If one of the values is a float, the result will also be a float.
3. Division (/): The division operator returns the result as a float, even if the division is exact. For example, 4 / 2 results in 2.0.
4. Floor Division (//): This operator performs integer division, discarding the decimal part and returning the largest integer less than or equal to the division result. If one of the operands is a float, the result will still be a float.
5. Modulo (%): This operator returns the remainder of a division. For example, 5 % 2 yields 1.
6. Addition (+) and Subtraction (-): These basic arithmetic operators perform their usual functions.
Operator Precedence
In Python, operators have different levels of priority, determining the order in which operations are performed. The order of precedence, from highest to lowest, is as follows:
- Exponentiation (**)
- Multiplication (*), Division (/), Floor Division (//), Modulo (%)
- Addition (+), Subtraction (-)
When operators have the same precedence level, Python evaluates them from left to right, except for exponentiation, which is evaluated from right to left. Additionally, operations within parentheses are always executed first.
Understanding Variables
Variables are essential for storing temporary results of expressions. In Python, a variable can be created by assigning a value or an expression to a name using the assignment operator (=). It’s important to note that:
- Variable names must start with a letter or an underscore (_).
- They cannot be reserved words in Python (such as if, else, while, etc.).
Creating and Updating Variables
Here’s an example of how to create and update variables:
var = 1 + 2 # var is now 3
var = 2 + 3 # var is now 5
var = 5 + 5 # var is now 10
print(var) # Output: 10
You can also assign values to multiple variables simultaneously:
a, b, c = 1, 2, 3 # a = 1, b = 2, c = 3
Updating Values Using Previous Values
You can use a variable’s current value to update it further. For instance:
var = 1 + 2 # var is now 3
var = var + 2 # var is now 5
var = var + 5 # var is now 10
print(var) # Output: 10
Instead of repeating the variable name, you can use a shorthand notation. For example:
var += 2 # This is equivalent to var = var + 2
Conclusion
Understanding operators, expressions, and variables is fundamental to programming in Python. These concepts enable you to perform calculations, store data, and create complex logic in your applications.