Python Loops
Table of Contents
Description
Loops in Python are used to repeatedly execute a block of code as long as a given condition is true or for a specified number of times. Python mainly supports:
for loop — Iterates over a sequence (like list, string, tuple)
while loop — Repeats as long as a condition is true
Special keywords: break, continue, pass
Prerequisites
- Understanding of conditional statements
- Familiarity with iterables (like lists, tuples, strings)
- Basic knowledge of Boolean logic
Examples
Here's a simple program in Python:
# For loop example: Print numbers 1 to 5
for i in range(1, 6):
print(i)
# While loop example: Print numbers until 5
count = 1
while count <= 5:
print(count)
count += 1
# Break statement: Exit loop when i == 3
for i in range(1, 6):
if i == 3:
break
print(i) # Prints 1, 2
# Continue statement: Skip number 3
for i in range(1, 6):
if i == 3:
continue
print(i) # Prints 1, 2, 4, 5
# Pass statement (placeholder)
for i in range(3):
pass # Does nothing for now
Real-World Applications
Data processing: Loop through files, rows, or entries.
Web scraping: Iterate through pages or elements.
Automation scripts: Repeatedly execute tasks.
Game development: Loops for movement, enemy behavior, or animations.
Monitoring systems: Continuously check device status or metrics.
Where topic Can Be Applied
Iterating datasets in Data Science and ML pipelines
Automation using scripts (e.g., file renaming, batch conversion)
Form submission and validations in web development
Control systems in embedded/robotics
Report generation and email campaigns
Resources
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Interview Questions
What is the difference between for and while loop?
When would you use break and continue?
How does Python's range() function work in loops?
What happens if the condition in a while loop is always true?
Can you iterate through a dictionary using a loop?