Loops (For & While)

Loops allow you to execute a block of code multiple times. Python makes looping very intuitive, especially when dealing with ranges of numbers or items in a list.

1. The for Loop

In Python, the for loop is primarily used for iterating. Instead of the "initialize-condition-increment" style found in C, Python's for loop iterates over a sequence (like a list or a range of numbers).

• range(start, stop, step): A built-in function that generates a sequence of numbers.

  • range(5) -> 0, 1, 2, 3, 4

  • range(1, 6) -> 1, 2, 3, 4, 5

2. The while Loop

The while loop repeats as long as a certain condition remains True. It is best used when you don't know exactly how many times you need to loop.

# --- FOR LOOP ---
print("For Loop (1 to 5):")
for i in range(1, 6):
    print(i, end=" ") # 'end' keeps the output on one line

print("\n\nIterating over a string:")
for letter in "PYTHON":
    print(letter)

# --- WHILE LOOP ---
print("\nWhile Loop:")
count = 5
while count > 0:
    print(f"T-minus {count}")
    count -= 1  # Important: Update the condition!
print("Blast off! 🚀")

3. Loop Control: break and continue

• break: Stops the loop entirely.

• continue: Skips the rest of the current iteration and jumps to the next one.

for num in range(1, 10):
    if num == 5:
        continue # Skip 5
    if num == 8:
        break    # Stop at 8
    print(num)