Loops and Conditionals

In Python, we often need to repeat actions or make decisions based on certain conditions. This is where loops and conditionals come in. Loops allow you to repeat a block of code, while conditionals let you run specific code only when certain conditions are met.

Conditionals: The If Statement

A conditional statement allows us to execute a block of code only if a certain condition is true. The basic structure is:

if condition:
    # code to run if condition is true
else:
    # code to run if condition is false

Here’s an example of using an if statement:

age = 18
if age >= 18:
    print("You are an adult")
else:
    print("You are a minor")

Explanation

In this example, the condition age >= 18 is evaluated. If it is true, the code under the if block is executed (printing "You are an adult"). If it is false, the code under the else block runs (printing "You are a minor"). This allows us to make decisions within our programs.

Loops: Repeating Actions

Loops help us execute a block of code multiple times. Python has several types of loops, with the for and while loops being the most common. Here’s an example using a for loop:

for i in range(5):
    print(i)

Explanation

The range(5) function generates numbers from 0 to 4, and the for loop repeats the print(i) statement for each number. Loops are especially useful when you need to perform a task multiple times or iterate over a collection of data.

Combining Loops and Conditionals

We can combine loops and conditionals to perform actions based on conditions during each iteration of a loop. Here’s an example that prints whether each number from 1 to 10 is even or odd:

for i in range(1, 11):
    if i % 2 == 0:
        print(i, "Even")
    else:
        print(i, "Odd")