Python Loops

In Python, loops are used to iterate over a sequence of values or to repeat a block of code a specified number of times. There are two types of loops in Python: for loops and while loops.

For Loops

The for loop is used to iterate over a sequence of values. The basic syntax for a for loop in Python is as follows:

for item in sequence:
    # code to be executed for each item in the sequenc

Here, sequence is the sequence of values to be iterated over, and item is a variable that will take on each value in the sequence in turn. For example, you might use a for loop to iterate over the characters in a string:

for char in "hello":
    print(char)

This code will output:

h
e
l
l
o

While Loops

The while loop is used to repeat a block of code as long as a specified condition is true. The basic syntax for a while loop in Python is as follows:

while condition:
    # code to be executed as long as the condition is true

Here, condition is the condition to be checked before each iteration of the loop. For example, you might use a while loop to repeat a block of code until a user enters a valid input:

while True:
    user_input = input("Enter a number between 1 and 10: ")
    if user_input.isdigit() and 1 <= int(user_input) <= 10:
        break
    else:
        print("Invalid input")

This code will keep asking the user to enter a number until they enter a valid number between 1 and 10.

Loop Control Statements

In addition to for and while loops, Python also provides several loop control statements that allow you to control the flow of a loop:

• break: Terminates the loop and exits the current block of code.
• continue: Skips the current iteration of the loop and moves on to the next one.
• pass: Does nothing and allows the loop to continue without executing any code.

For example, the following code will print the numbers from 0 to 4, but will skip the number 2:

for num in range(5):
    if num == 2:
        continue
    print(num)

This code will output:
0
1
3
4