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| Python control statements tutorial explaining if, for loop, while loop, match case, and practical examples in simple English. |
Control Flow means the order in which statements execute in a program. Control statements help us make decisions and repeat tasks.
1️⃣ If Statement
If statement is used to make decisions. We use it when we want to execute code only if a condition is true.
📌 Where we use it?
- Validating input
- Checking conditions
- Making decisions
Example:
age = 18
if age >= 18:
print("You can vote")
else:
print("You cannot vote")
2️⃣ For Loop
For loop is used when we know how many times we want to repeat. It works with list, tuple, set, range.
📌 Where we use it?
- Loop through list items
- Print numbers in range
- Process collections
Example:
for i in range(1, 6):
print(i)
3️⃣ While Loop
While loop is used when we don’t know how many times to repeat. It runs while condition is true.
📌 Where we use it?
- User input loops
- Menu driven programs
- Unknown iteration count
Example:
count = 1
while count <= 5:
print(count)
count += 1
4️⃣ Do While Loop
Python does NOT have a direct do-while loop. But we can simulate it using while True.
📌 Where we use it?
- Run code at least once
- Menu programs
Example:
while True:
num = int(input("Enter positive number: "))
if num > 0:
print("Valid number")
break
5️⃣ Match Case
Match case is like switch statement. It is cleaner than multiple if-else.
📌 Where we use it?
- Menu selection
- Multiple fixed values
- Pattern matching
Example:
day = 2
match day:
case 1:
print("Monday")
case 2:
print("Tuesday")
case _:
print("Other day")
6️⃣ Foreach Loop
Python does not use the word foreach, but for loop works like foreach.
Example:
names = ["Anna", "John", "Sam"]
for name in names:
print(name)
📌 Extra Practical Examples
✔ Circumference of Circle (With Validation)
r = float(input("Enter radius: "))
if r > 0:
pi = 3.14
circumference = 2 * pi * r
print("Circumference =", circumference)
else:
print("Radius must be positive")
✔ Hypotenuse of Right Triangle
a = float(input("Enter first side: "))
b = float(input("Enter second side: "))
c = (a*a + b*b) ** 0.5
print("Hypotenuse =", c)
✔ Largest of 3 Numbers
n1 = 60
n2 = 50
n3 = 30
if n1 > n2 and n1 > n3:
print(n1)
elif n2 > n1 and n2 > n3:
print(n2)
else:
print(n3)
✔ Even Numbers Using For Loop
my_list = [7, 22, 14, 9, 8, 21, 13]
for i in my_list:
if i % 2 == 0:
print(i)
✔ Linear Search with Break
target = 43
my_list = [2,5,4,6,10,9]
for i in my_list:
if i == target:
print("Found")
break
else:
print("Not Found")
✔ Sum Until User Enters 0 (While Loop)
total = 0
while True:
num = int(input("Enter number: "))
if num == 0:
break
total += num
print("Total =", total)
🎯 Control statements are the heart of programming. They help us build logical, dynamic and interactive programs 🚀.