Day 2: Control Flow & Loops – Python 30-Day Challenge ??

Welcome to Day 2 of my Python learning journey! Today, I explored one of the most powerful concepts in programming: Control Flow & Loops. These structures allow us to make decisions in our code and repeat actions efficiently.

What I Learned Today

Conditional Statements (if-else)

Python supports the usual logic conditions used in mathematics: ? Equals: a == b ? Not Equals: a != b ? Less than: a < b ? Less than or equal to: a <= b ? Greater than: a > b ? Greater than or equal to: a >= b

These are commonly used with if statements and loops, making them essential for decision-making in Python.

?? Python’s If-Else Structure

x = 10  
if x > 5:  
    print("x is greater than 5")  
elif x == 5:  
    print("x is equal to 5")  
else:  
    print("x is less than 5")  
        

?? Python relies on indentation (whitespace) to define blocks of code instead of curly braces {} like in other languages.

?? Ternary Operators (Short-Hand If-Else)

Python allows one-liner if-else statements for concise logic.

age = 18  
status = "Adult" if age >= 18 else "Minor"  
print(status)  # Output: Adult  
        

?? Logical Operators

? and: Returns True if both conditions are True. ? or: Returns True if at least one condition is True. ? not: Reverses the result (True becomes False, and vice versa).

Example:

a = 10  
b = 5  
if a > 5 and b < 10:  
    print("Both conditions are met!")  
        

?? Loops in Python

Loops allow us to repeat tasks efficiently. Python provides two main types:

1?? While Loop – Runs While a Condition is True

x = 1  
while x <= 5:  
    print(x)  
    x += 1  # Don’t forget to increment, or it will loop forever!  
        

?? Break Statement: Stops the loop before the condition becomes False. ?? Continue Statement: Skips the current iteration and moves to the next.

Example:

x = 0  
while x < 5:  
    x += 1  
    if x == 3:  
        continue  # Skip when x is 3  
    print(x)  
        

2?? For Loop – Iterates Over Sequences

fruits = ["apple", "banana", "cherry"]  
for fruit in fruits:  
    print(fruit)  
        

?? Looping Through a String: Strings are iterable, meaning we can loop through their characters.

for char in "Python":  
    print(char)  
        

?? Using range() in For Loops The range() function helps iterate over a sequence of numbers.

for num in range(1, 6):  # Loops from 1 to 5  
    print(num)  
        

? We can define start, stop, and step values in range().

for num in range(2, 10, 2):  # Start at 2, end before 10, step by 2  
    print(num)  
        

?? Else in Loops: Runs when the loop finishes normally (i.e., not interrupted by break).

for x in range(5):  
    print(x)  
else:  
    print("Loop completed!")  
        

?? Nested Loops: A loop inside another loop.

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

?? Pass Statement: Used to prevent syntax errors when a loop must exist but does nothing yet.

for x in range(5):  
    pass  # Placeholder for future code  
        

?? Exercise: Putting It into Practice

? 1. Check If a Number is Even or Odd

num = int(input("Enter a number: "))  
if num % 2 == 0:  
    print(f"{num} is even")  
else:  
    print(f"{num} is odd")  
        

? 2. Print Numbers from 1 to 20, Skipping Multiples of 3

for i in range(1, 21):  
    if i % 3 == 0:  
        continue  # Skip multiples of 3  
    print(i)  
        

?? Resources Used

?? Python Loops (W3Schools)

Final Thoughts

Today was all about making decisions and repeating tasks efficiently in Python. Learning if-else conditions and loops gives us the power to write dynamic, intelligent programs.

?? Next up: Functions & Modules! Can’t wait to dive deeper. If you have any tips or feedback, drop a comment below! Let’s keep learning together. ??

#Python #Day2 #30DayChallenge #Learning #Coding #Programming #PythonForBeginners