Built-in Functions

🐍 Python’s Built-in Toolbox: Your Magic Helper Functions

Imagine you have a magical toolbox. Inside are special tools that can sort things, count stuff, decode secret messages, and even check if everyone agrees! Let’s open this toolbox together.

🎯 The Big Picture

Python gives you built-in functions — ready-to-use tools that save you from writing complicated code. Think of them like kitchen gadgets: instead of chopping vegetables by hand, you use a food processor!

Today we’ll explore 6 amazing tool groups:

1. 📊 sorted & reversed — Organizing things in order
2. 🔢 min, max & sum — Finding champions and totals
3. 🔄 Number Base Conversions — Speaking different number languages
4. 🔤 chr & ord — Secret codes between letters and numbers
5. 🎒 Attribute Access — Peeking inside objects
6. ✅ all & any — Group voting systems

📊 sorted() and reversed() — The Organizers

The Story

Imagine your toy box is messy. You want to arrange toys from smallest to biggest. That’s what sorted() does!

And reversed()? It’s like reading a book backwards — last page first!

sorted() — Put Things in Order

# Messy numbers
messy = [5, 2, 8, 1, 9]

# sorted() arranges them!
neat = sorted(messy)
print(neat)  # [1, 2, 5, 8, 9]

Cool tricks:

# Reverse order (biggest first)
big_first = sorted(messy, reverse=True)
print(big_first)  # [9, 8, 5, 2, 1]

# Sort words alphabetically
fruits = ["banana", "apple", "cherry"]
print(sorted(fruits))
# ['apple', 'banana', 'cherry']

reversed() — Flip Everything Around

# Original list
colors = ["red", "green", "blue"]

# Flip it backwards
flipped = list(reversed(colors))
print(flipped)
# ['blue', 'green', 'red']

Remember: reversed() gives you an iterator, so wrap it with list() to see results!

🎭 The Key Difference

🔢 min(), max() & sum() — The Number Champions

The Story

Imagine a race. Who came first (min time)? Who was last (max time)? What’s the total time for everyone?

min() — Find the Smallest

scores = [85, 92, 78, 96, 88]
lowest = min(scores)
print(lowest)  # 78

max() — Find the Biggest

scores = [85, 92, 78, 96, 88]
highest = max(scores)
print(highest)  # 96

sum() — Add Everything Together

scores = [85, 92, 78, 96, 88]
total = sum(scores)
print(total)  # 439

# Bonus: Start with extra points!
total_plus_bonus = sum(scores, 10)
print(total_plus_bonus)  # 449

🎯 Quick Combo Example

prices = [4.99, 2.50, 8.75, 1.25]

print(f"Cheapest: ${min(prices)}")
print(f"Most expensive: ${max(prices)}")
print(f"Total: ${sum(prices)}")

Output:

Cheapest: $1.25
Most expensive: $8.75
Total: $17.49

🔄 Number Base Conversions — Speaking Different Languages

The Story

Numbers can wear different costumes!

• Binary (base 2): Only uses 0 and 1 (like light switches)
• Octal (base 8): Uses 0-7 (old computer style)
• Hexadecimal (base 16): Uses 0-9 and A-F (colors in websites!)

bin() — Convert to Binary

number = 10
binary = bin(number)
print(binary)  # '0b1010'

# 10 in binary is 1010!

oct() — Convert to Octal

number = 10
octal = oct(number)
print(octal)  # '0o12'

# 10 in octal is 12!

hex() — Convert to Hexadecimal

number = 255
hexadecimal = hex(number)
print(hexadecimal)  # '0xff'

# 255 in hex is ff!

int() — Convert Back to Decimal

# From binary
print(int('1010', 2))   # 10

# From octal
print(int('12', 8))     # 10

# From hex
print(int('ff', 16))    # 255

🎨 Fun Fact: Web Colors!

# Red in RGB: 255, 0, 0
red = hex(255)[2:]    # 'ff'
green = hex(0)[2:]    # '0'
blue = hex(0)[2:]     # '0'

# Web color needs 2 digits each
color = f"#{red:0>2}{green:0>2}{blue:0>2}"
print(color)  # #ff0000 (pure red!)

🔤 chr() and ord() — The Secret Code Machines

The Story

Every letter has a secret number! A is 65, a is 97, and so on. These are ASCII codes.

• chr() turns a number INTO a letter
• ord() turns a letter INTO a number

chr() — Number → Character

print(chr(65))   # 'A'
print(chr(97))   # 'a'
print(chr(49))   # '1' (the character)
print(chr(128512)) # '😀' (emoji!)

ord() — Character → Number

print(ord('A'))  # 65
print(ord('a'))  # 97
print(ord('1'))  # 49
print(ord('😀')) # 128512

🕵️ Secret Message Example

# Simple cipher: shift each letter by 1
def encode(message):
    result = ""
    for char in message:
        # Shift to next character
        result += chr(ord(char) + 1)
    return result

def decode(message):
    result = ""
    for char in message:
        result += chr(ord(char) - 1)
    return result

secret = encode("HELLO")
print(secret)  # 'IFMMP'

original = decode(secret)
print(original)  # 'HELLO'

🎒 Attribute Access Functions — Peeking Inside Objects

The Story

Objects in Python are like backpacks. They have stuff inside (attributes) and can do things (methods). These functions help you look inside!

hasattr() — Does it have this?

class Dog:
    def __init__(self):
        self.name = "Buddy"
        self.age = 3

dog = Dog()

# Check if dog has 'name'
print(hasattr(dog, 'name'))   # True
print(hasattr(dog, 'wings'))  # False

getattr() — Get something from inside

dog = Dog()

# Get the name attribute
name = getattr(dog, 'name')
print(name)  # 'Buddy'

# With default if missing
wings = getattr(dog, 'wings', 'None!')
print(wings)  # 'None!'

setattr() — Put something inside

dog = Dog()

# Add a new attribute
setattr(dog, 'breed', 'Golden Retriever')
print(dog.breed)  # 'Golden Retriever'

# Change existing attribute
setattr(dog, 'age', 4)
print(dog.age)  # 4

delattr() — Remove something

dog = Dog()
dog.nickname = "Bud"

# Remove the nickname
delattr(dog, 'nickname')

# dog.nickname would now error!

🛠️ Why Use These?

# Dynamic attribute names!
attribute_name = input("What info? ")

if hasattr(dog, attribute_name):
    value = getattr(dog, attribute_name)
    print(f"{attribute_name}: {value}")
else:
    print("Dog doesn't have that!")

✅ all() and any() — The Voting Booth

The Story

Imagine a group making decisions:

• all() = Everyone must agree (unanimous vote)
• any() = At least one person agrees (any vote counts)

all() — Does EVERYONE agree?

# All must be True
votes = [True, True, True]
print(all(votes))  # True

# One disagreement breaks it
votes = [True, False, True]
print(all(votes))  # False

any() — Does ANYONE agree?

# At least one True
votes = [False, False, True]
print(any(votes))  # True

# Nobody agrees
votes = [False, False, False]
print(any(votes))  # False

🎯 Real-World Examples

# Check if all scores pass (≥60)
scores = [75, 82, 91, 68]
all_passed = all(score >= 60 for score in scores)
print(all_passed)  # True

# Check if any student got 100
scores = [75, 82, 100, 68]
has_perfect = any(score == 100 for score in scores)
print(has_perfect)  # True

📋 Quick Reference Table

🎁 Putting It All Together

# Fun example using multiple functions!
data = [5, 2, 8, 1, 9]

# Sort and reverse
ordered = sorted(data)
backwards = list(reversed(ordered))

# Stats
print(f"Min: {min(data)}, Max: {max(data)}")
print(f"Sum: {sum(data)}")

# Check conditions
all_positive = all(x > 0 for x in data)
any_big = any(x > 7 for x in data)

print(f"All positive? {all_positive}")
print(f"Any > 7? {any_big}")

🧠 Remember This!

graph LR
    A["Built-in Functions"] --> B["Organizing"]
    A --> C["Math Helpers"]
    A --> D["Number Bases"]
    A --> E["Character Codes"]
    A --> F["Object Access"]
    A --> G["Logic Checks"]

    B --> B1["sorted - new sorted list"]
    B --> B2["reversed - flip iterator"]

    C --> C1["min - smallest"]
    C --> C2["max - biggest"]
    C --> C3["sum - add all"]

    D --> D1["bin - to binary"]
    D --> D2["oct - to octal"]
    D --> D3["hex - to hexadecimal"]

    E --> E1["chr - number→letter"]
    E --> E2["ord - letter→number"]

    F --> F1["hasattr - check exists"]
    F --> F2["getattr - get value"]
    F --> F3["setattr - set value"]
    F --> F4["delattr - remove"]

    G --> G1["all - everyone agrees"]
    G --> G2["any - someone agrees"]

🚀 You Did It!

Now you have 6 powerful tool groups in your Python toolbox:

1. sorted/reversed — Organize anything!
2. min/max/sum — Quick math on collections
3. bin/oct/hex — Number costume changes
4. chr/ord — Letter-number secret codes
5. hasattr/getattr/setattr/delattr — Object explorers
6. all/any — Smart voting on conditions

These tools make your code shorter, cleaner, and more Pythonic. Practice using them, and soon they’ll feel like second nature!

Happy coding! 🐍✨