Python Basics: Loops, Functions, Variables, and Conditionals

Python Basics

When working with Python, one often encounters loops, functions, data types, variables, conditional and control statements, among other things. Loops allow us to repeat a block of code until a condition is met; functions enable us to organize and reuse blocks of code; data types define the kind of value a variable holds; variables store values; conditional and control statements determine the flow of execution in a program.

Functions in Python

Functions are building blocks of programs. They help us avoid repeating the same code elsewhere. Instead, we can simply call the function again when we need similar functionality.

Here's an example of a simple function in Python:

def greet():
    print("Welcome to the world of Python")
greet()

This greet function will always print "Welcome to the world of Python." Each time you call the greet function, it executes the statement inside the parentheses.

Working With Variables in Python

Variables hold values. For instance, let's say we want to calculate the perimeter of a square. To do that, we'll declare two variables: side, representing the length of each side, and perim, holding the result of the calculation:

side = 3.5
perim = 4 * side
print(perim)  # Output: 14

In this code snippet, we assign the number 3.5 to the variable side. Then we multiply side by 4, storing the result in perim. Finally, we display the value stored in perim, which is 14.

Conditionals and Control Statements

Conditionals and control statements govern the order in which parts of a program execute. Consider the following code:

age = 21
if age > 18:
    print("Adult")
else:
    print("Underage")

Here, the if statement checks if the age variable exceeds 18. If it does, the program prints "Adult", otherwise it prints "Underage". This shows how conditionals help direct the flow of your program.

These basic concepts provide fundamental building blocks for creating complex applications with Python.