for Loop

A for loop is used to repeat a block of code a fixed number of times.

It is helpful when we already know how many times we want to run the loop.

• The loop uses a loop variable that changes value in each step
• It works with sequences like numbers, lists, or strings
• The range() function is commonly used with for loops
• It makes programs shorter and avoids repeated code

Explanation

• The loop starts from a number and goes step by step
• It stops when the limit is reached
• Each time, the loop variable changes its value

Real-Life Scenario

• Teacher calling roll numbers from 1 to 30
• Printing numbers from 1 to 10
• Showing marks of students one by one

 Instead of writing print() many times, we use a loop

Syntax

for variable in range(start, end):
    # code

Example 1

for i in range(1, 6):
    print(i)

Output

1
2
3
4
5

Example 2

total = 0

for i in range(1, 6):
    total = total + i

print(total)

Output

15

Explanation of Example

• range(1, 6) → gives numbers 1 to 5
• Loop adds all numbers → 1+2+3+4+5 = 15

Why for loop is Important

• Saves time by avoiding repeated code
• Helps in counting and iteration
• Used in real-world programs
• Builds logical thinking

Common Beginner Mistakes

• Forgetting that end value is not included
• Wrong indentation
• Using wrong range values
• Not understanding loop flow

➤ Key Points

• for loop repeats code fixed number of times
• Works with range() function
• Loop variable changes in each step
• Stops automatically when range ends
• Best for counting loops (1 to 10, etc.)
• Easy and safe to use

➤ Tips

• Use for loop when count is known
• range(start, end) → end value is not included
• Example: range(1, 5) → gives 1, 2, 3, 4
• Always use proper indentation
• Use meaningful variable names like i, num
• Good for printing numbers, lists, and tables