# macOS (Homebrew)
brew install python3

# Ubuntu/Debian
sudo apt-get install python3

# Verify installation
python3 --version

# Interactive shell
python3

# Run a file
python3 script.py

# Run directly
./script.py  # Add #!/usr/bin/env python3 at top

# No type declaration needed
name = "Alice"
age = 25
height = 5.7
is_student = True

# Multiple assignment
x, y, z = 1, 2, 3

# Same value
a = b = c = 0

# Integer
count = 42
big_number = 1_000_000  # Underscores for readability

# Float
price = 19.99
scientific = 3.14e-10

# Complex
complex_num = 3 + 4j

# Operations
sum_val = 10 + 5      # 15
diff = 10 - 5         # 5
product = 10 * 5      # 50
quotient = 10 / 3     # 3.333...
floor_div = 10 // 3   # 3
remainder = 10 % 3    # 1
power = 2 ** 3        # 8

# Single or double quotes
name = 'Alice'
message = "Hello World"

# Multi-line
text = """This is
a multi-line
string"""

# String operations
greeting = "Hello" + " " + "World"  # Concatenation
repeat = "Ha" * 3                   # "HaHaHa"

# String methods
text = "hello world"
print(text.upper())          # "HELLO WORLD"
print(text.capitalize())     # "Hello world"
print(text.title())          # "Hello World"
print(text.replace("world", "Python"))  # "hello Python"
print(text.split())          # ['hello', 'world']
print("  spaces  ".strip())  # "spaces"

# String indexing and slicing
text = "Python"
print(text[0])      # "P"
print(text[-1])     # "n"
print(text[0:3])    # "Pyt"
print(text[2:])     # "thon"
print(text[:4])     # "Pyth"

# F-strings (formatted strings)
name = "Alice"
age = 25
print(f"My name is {name} and I'm {age} years old")
print(f"Next year I'll be {age + 1}")

is_valid = True
is_empty = False

# Boolean operations
print(True and False)   # False
print(True or False)    # True
print(not True)         # False

# Comparison operators
print(5 > 3)            # True
print(5 < 3)            # False
print(5 == 5)           # True
print(5 != 3)           # True
print(5 >= 5)           # True

# Create list
fruits = ["apple", "banana", "cherry"]
numbers = [1, 2, 3, 4, 5]
mixed = [1, "hello", True, 3.14]

# Access elements
print(fruits[0])        # "apple"
print(fruits[-1])       # "cherry"

# Slicing
print(numbers[1:4])     # [2, 3, 4]
print(numbers[:3])      # [1, 2, 3]
print(numbers[2:])      # [3, 4, 5]

# Modify
fruits[0] = "orange"
fruits.append("grape")
fruits.insert(1, "mango")
fruits.remove("banana")
popped = fruits.pop()   # Remove and return last

# List methods
numbers = [3, 1, 4, 1, 5]
numbers.sort()          # [1, 1, 3, 4, 5]
numbers.reverse()       # [5, 4, 3, 1, 1]
print(numbers.count(1)) # 2
print(numbers.index(4)) # 2

# List operations
list1 = [1, 2]
list2 = [3, 4]
combined = list1 + list2        # [1, 2, 3, 4]
repeated = [0] * 3              # [0, 0, 0]
print(3 in [1, 2, 3])           # True
print(len([1, 2, 3]))           # 3

# List comprehension
squares = [x**2 for x in range(5)]              # [0, 1, 4, 9, 16]
evens = [x for x in range(10) if x % 2 == 0]   # [0, 2, 4, 6, 8]

# Create tuple
point = (3, 4)
person = ("Alice", 25, "Engineer")

# Access elements
print(point[0])         # 3

# Unpacking
x, y = point
name, age, job = person

# Tuple methods
numbers = (1, 2, 3, 2, 1)
print(numbers.count(2))  # 2
print(numbers.index(3))  # 2

# Create dictionary
user = {
    "name": "Alice",
    "age": 25,
    "city": "New York"
}

# Access values
print(user["name"])          # "Alice"
print(user.get("age"))       # 25
print(user.get("email", "N/A"))  # "N/A" (default)

# Modify
user["age"] = 26
user["email"] = "alice@example.com"

# Delete
del user["city"]
removed = user.pop("email")

# Dictionary methods
print(user.keys())           # dict_keys(['name', 'age'])
print(user.values())         # dict_values(['Alice', 26])
print(user.items())          # dict_items([('name', 'Alice'), ('age', 26)])

# Check existence
print("name" in user)        # True

# Dictionary comprehension
squares = {x: x**2 for x in range(5)}  # {0: 0, 1: 1, 2: 4, 3: 9, 4: 16}

# Create set
fruits = {"apple", "banana", "cherry"}
numbers = {1, 2, 3, 4, 5}

# Add and remove
fruits.add("orange")
fruits.remove("banana")  # Error if not exists
fruits.discard("grape")  # No error if not exists

# Set operations
set1 = {1, 2, 3}
set2 = {3, 4, 5}

print(set1 | set2)      # Union: {1, 2, 3, 4, 5}
print(set1 & set2)      # Intersection: {3}
print(set1 - set2)      # Difference: {1, 2}
print(set1 ^ set2)      # Symmetric difference: {1, 2, 4, 5}

age = 18

if age >= 18:
    print("Adult")
elif age >= 13:
    print("Teenager")
else:
    print("Child")

# Ternary operator
status = "Adult" if age >= 18 else "Minor"

# Loop through list
fruits = ["apple", "banana", "cherry"]
for fruit in fruits:
    print(fruit)

# Loop with range
for i in range(5):      # 0 to 4
    print(i)

for i in range(2, 10, 2):  # 2, 4, 6, 8
    print(i)

# Loop with index
for i, fruit in enumerate(fruits):
    print(f"{i}: {fruit}")

# Loop through dictionary
user = {"name": "Alice", "age": 25}
for key, value in user.items():
    print(f"{key}: {value}")

count = 0
while count < 5:
    print(count)
    count += 1

# Break and continue
for i in range(10):
    if i == 3:
        continue  # Skip this iteration
    if i == 7:
        break     # Exit loop
    print(i)

# Define function
def greet(name):
    return f"Hello, {name}!"

# Call function
message = greet("Alice")
print(message)

# Default parameters
def power(base, exponent=2):
    return base ** exponent

print(power(5))        # 25
print(power(5, 3))     # 125

# Multiple return values
def get_coordinates():
    return 10, 20

x, y = get_coordinates()

# *args (variable arguments)
def sum_all(*numbers):
    return sum(numbers)

print(sum_all(1, 2, 3, 4))  # 10

# **kwargs (keyword arguments)
def print_info(**info):
    for key, value in info.items():
        print(f"{key}: {value}")

print_info(name="Alice", age=25, city="NYC")

# Lambda functions
square = lambda x: x ** 2
print(square(5))  # 25

add = lambda x, y: x + y
print(add(3, 4))  # 7

# Write file
with open("file.txt", "w") as f:
    f.write("Hello World\n")
    f.write("Second line\n")

# Read file
with open("file.txt", "r") as f:
    content = f.read()
    print(content)

# Read lines
with open("file.txt", "r") as f:
    for line in f:
        print(line.strip())

# Read all lines
with open("file.txt", "r") as f:
    lines = f.readlines()

# Append to file
with open("file.txt", "a") as f:
    f.write("Appended line\n")

# Try-except
try:
    result = 10 / 0
except ZeroDivisionError:
    print("Cannot divide by zero")

# Multiple exceptions
try:
    value = int("abc")
except (ValueError, TypeError) as e:
    print(f"Error: {e}")

# Finally block
try:
    file = open("file.txt", "r")
    content = file.read()
except FileNotFoundError:
    print("File not found")
finally:
    file.close()  # Always executes

# Raise exceptions
def divide(a, b):
    if b == 0:
        raise ValueError("Cannot divide by zero")
    return a / b

# Define class
class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def greet(self):
        return f"Hello, I'm {self.name}"

    def is_adult(self):
        return self.age >= 18

# Create object
person = Person("Alice", 25)
print(person.name)           # "Alice"
print(person.greet())        # "Hello, I'm Alice"
print(person.is_adult())     # True

# Inheritance
class Student(Person):
    def __init__(self, name, age, student_id):
        super().__init__(name, age)
        self.student_id = student_id

    def study(self):
        return f"{self.name} is studying"

student = Student("Bob", 20, "S12345")
print(student.greet())       # Inherited method
print(student.study())       # Own method

# Import module
import math
print(math.sqrt(16))     # 4.0
print(math.pi)           # 3.14159...

# Import specific items
from math import sqrt, pi
print(sqrt(16))

# Import with alias
import numpy as np

# Import all (not recommended)
from math import *

# Create your own module (mymodule.py)
# def greet(name):
#     return f"Hello, {name}"

# Use it
import mymodule
print(mymodule.greet("Alice"))

# Basic
squares = [x**2 for x in range(10)]

# With condition
evens = [x for x in range(10) if x % 2 == 0]

# With transformation
words = ["hello", "world"]
upper_words = [word.upper() for word in words]

# Nested
matrix = [[i*j for j in range(3)] for i in range(3)]

# Dictionary comprehension
squares_dict = {x: x**2 for x in range(5)}

# Set comprehension
unique_lengths = {len(word) for word in ["hello", "world", "hi"]}

# Type conversion
int("42")           # 42
float("3.14")       # 3.14
str(42)             # "42"
list("abc")         # ['a', 'b', 'c']

# Math functions
abs(-5)             # 5
min(1, 2, 3)        # 1
max(1, 2, 3)        # 3
sum([1, 2, 3])      # 6
round(3.7)          # 4
pow(2, 3)           # 8

# Sequence functions
len([1, 2, 3])      # 3
sorted([3, 1, 2])   # [1, 2, 3]
reversed([1, 2, 3]) # [3, 2, 1]
enumerate(['a', 'b', 'c'])  # [(0, 'a'), (1, 'b'), (2, 'c')]
zip([1, 2], ['a', 'b'])     # [(1, 'a'), (2, 'b')]

# Type checking
type(42)            # <class 'int'>
isinstance(42, int) # True

# Input
name = input("Enter name: ")