Sprint 2 - Iterations (Python)

• ✨ Iterations in Python ✨
  • What are Iterations?
  • The for Loop
  • Loop Control Statements
  • Nested Loops
  • enumerate() for Indexed Iteration
• Interactive Demo
• Learn Iterations (Loops)
  • About Iteration in Python
  • For Loop Example (for i in range(n))
  • While Loop Example (while condition)

✨ Iterations in Python ✨

What are Iterations?

Iteration means repeating a set of instructions multiple times. In Python, iteration is most often done with loops, which let us run the same block of code several times.

There are two main kinds of loops:

• for loops → iterate over items in a sequence (list, string, range, etc.)
• while loops → keep repeating as long as a condition is True

The for Loop

A for loop goes through items in a sequence one by one.

# Example: Iterating through a list
fruits = ["apple", "banana", "cherry"]

for fruit in fruits:
    print(fruit)

apple
banana
cherry

We can also iterate over numbers with range():

for i in range(5):  # counts from 0 to 4
    print(i)

0
1
2
3
4

The While Loop

A While loop runs until its condition becomes False:

count = 0

while count < 5:
    print("Count is:", count)
    count += 1

Count is: 0
Count is: 1
Count is: 2
Count is: 3
Count is: 4

Loop Control Statements

We can control loops using special keywords:

• break → stop the loop completely
• continue → skip to the next iteration
• pass → do nothing (acts as a placeholder)

Nested Loops

A loop inside another loop:

for i in range(2):       # outer loop
    for j in range(3):   # inner loop
        print(f"i={i}, j={j}")

i=0, j=0
i=0, j=1
i=0, j=2
i=1, j=0
i=1, j=1
i=1, j=2

enumerate() for Indexed Iteration

When looping over lists, we often need both the index and the item. enumerate() gives us both at the same time.

fruits = ["apple", "banana", "cherry"]

for index, fruit in enumerate(fruits):
    print(index, fruit)

0 apple
1 banana
2 cherry

Interactive Demo

Learn Iterations (Loops)

About Iteration in Python

Iteration means repeating a block of code multiple times. Python provides two main loop structures:

• for loops – repeat a block for each item in a sequence or range.
• while loops – repeat a block as long as a condition is True.

For Loop Example (for i in range(n))

This loop prints numbers from 0 to n-1.

Enter n:

While Loop Example (while condition)

This loop keeps adding numbers until the sum exceeds a limit.

Limit: