Python Loops – Repeating Code Efficiently

Loops are essential for repeating code without writing the same lines over and over. Python offers two main types of loops: for loops and while loops.

For Loops

For loops iterate over a sequence (like a list or range):

# Loop through a list
fruits = ["apple", "banana", "orange"]
for fruit in fruits:
    print(f"I like {fruit}")

# Loop through a range of numbers
for i in range(5):
    print(f"Count: {i}")  # Prints 0 to 4

Range Function

The range() function generates sequences of numbers:

range(5)        # 0, 1, 2, 3, 4
range(1, 6)     # 1, 2, 3, 4, 5
range(0, 10, 2) # 0, 2, 4, 6, 8 (step by 2)

While Loops

While loops continue as long as a condition is true:

count = 0
while count < 5:
    print(f"Count is {count}")
    count += 1  # Important: update the condition!

Loop Control

Use break and continue to control loop behavior:

# Break: exit the loop early
for i in range(10):
    if i == 5:
        break
    print(i)  # Prints 0 to 4

# Continue: skip to next iteration
for i in range(5):
    if i == 2:
        continue
    print(i)  # Prints 0, 1, 3, 4

Practical Example

# Calculate sum of numbers
numbers = [1, 2, 3, 4, 5]
total = 0
for num in numbers:
    total += num
print(f"Sum: {total}")  # Sum: 15

Loops save time and make your code more efficient by automating repetitive tasks.