for

Syntax

for variable in iterable:
    # code to execute for each item

Examples

fruits = ["apple", "banana", "orange", "grape"]

for fruit in fruits:
    print(f"I like {fruit}")

numbers = [1, 2, 3, 4, 5]
total = 0

for num in numbers:
    total += num

print(f"Sum: {total}")  # 15

# Count from 0 to 4
for i in range(5):
    print(i)  # 0, 1, 2, 3, 4

# Count from 1 to 5
for i in range(1, 6):
    print(i)  # 1, 2, 3, 4, 5

# Count by steps
for i in range(0, 10, 2):
    print(i)  # 0, 2, 4, 6, 8

# Countdown
for i in range(5, 0, -1):
    print(f"{i}...")  # 5... 4... 3... 2... 1...
print("Liftoff!")

message = "Python"

for char in message:
    print(char)  # P, y, t, h, o, n

# Count vowels
text = "Hello World"
vowels = "aeiouAEIOU"
vowel_count = 0

for char in text:
    if char in vowels:
        vowel_count += 1

print(f"Vowels found: {vowel_count}")

fruits = ["apple", "banana", "orange"]

for index, fruit in enumerate(fruits):
    print(f"{index + 1}. {fruit}")
# Output:
# 1. apple
# 2. banana
# 3. orange

# Start counting from different number
for index, fruit in enumerate(fruits, start=10):
    print(f"Item {index}: {fruit}")

student_scores = {
    "Alice": 85,
    "Bob": 92,
    "Charlie": 78
}

# Iterate over keys
for name in student_scores:
    print(f"{name}: {student_scores[name]}")

# Iterate over values
for score in student_scores.values():
    print(f"Score: {score}")

# Iterate over key-value pairs
for name, score in student_scores.items():
    print(f"{name} scored {score}")
    if score >= 90:
        print("  Excellent!")

# Multiplication table
for i in range(1, 4):
    for j in range(1, 4):
        product = i * j
        print(f"{i} × {j} = {product}")
    print()  # Empty line between tables

# Pattern printing
for row in range(1, 5):
    for col in range(row):
        print("*", end=" ")
    print()  # New line after each row

# Break - exit loop early
for num in range(1, 11):
    if num == 5:
        print("Found 5! Stopping...")
        break
    print(num)

print()

# Continue - skip to next iteration
for num in range(1, 6):
    if num == 3:
        continue  # Skip 3
    print(num)  # Prints 1, 2, 4, 5

print()

# Practical example
passwords = ["abc", "password123", "12345", "secure_pass"]

for pwd in passwords:
    if len(pwd) < 8:
        print(f"{pwd} - Too short, skipping...")
        continue
    print(f"{pwd} - Valid password")
    if pwd == "secure_pass":
        print("Found secure password!")
        break

Best practices

• Use descriptive variable names in for loops (for student in students: instead of for s in students:)
• Use enumerate() when you need both index and value
• Prefer list comprehensions for simple transformations ([x*2 for x in numbers])
• Avoid modifying the list you're iterating over - create a new list instead
• Use range(len(list)) only when absolutely necessary - prefer direct iteration
• Break complex nested loops into separate functions for better readability

At a glance

Purpose

Scripting and general-purpose applications

File extension

.py

Runs in

Python interpreter

Usually used with

Python standard library and packages

Specifications & further reading

• Python language reference

Related Python documentation