Python Programming: Getting Started Guide

1print('Hello, World!')

1if 5 > 2:
2    print("Five is greater than two!")
3    print("This is still part of the if block")
4print("This is outside the if block")

1# This is a comment
2print("Hello, World!")  # This is an inline comment

1# Integer
2x = 10
3print(x, type(x))
4
5# Float
6y = 10.5
7print(y, type(y))
8
9# Complex
10z = 1j
11print(z, type(z))

1# String
2name = "Python"
3print(name, type(name))
4
5# String methods
6print(name.upper())
7print(name.lower())
8print(len(name))

1# List (mutable)
2fruits = ["apple", "banana", "cherry"]
3print(fruits, type(fruits))
4fruits.append("orange")
5print(fruits)
6
7# Tuple (immutable)
8coordinates = (10, 20)
9print(coordinates, type(coordinates))
10
11# Range
12numbers = range(5)
13print(list(numbers), type(numbers))

1# Dictionary
2person = {
3    "name": "John",
4    "age": 30,
5    "city": "New York"
6}
7print(person, type(person))
8print(person["name"])

1# Set (unordered, no duplicates)
2fruits_set = {"apple", "banana", "cherry", "apple"}
3print(fruits_set, type(fruits_set))  # Note: duplicates are removed

1# Boolean
2is_python_fun = True
3print(is_python_fun, type(is_python_fun))

1age = 18
2
3if age < 18:
4    print("You are a minor")
5elif age == 18:
6    print("You just became an adult")
7else:
8    print("You are an adult")

1# Looping through a list
2fruits = ["apple", "banana", "cherry"]
3for fruit in fruits:
4    print(fruit)
5
6# Looping through a range
7for i in range(5):
8    print(i)  # Prints 0, 1, 2, 3, 4

1# While loop
2count = 0
3while count < 5:
4    print(count)
5    count += 1  # Increment count

1# Break statement
2for i in range(10):
3    if i == 5:
4        break  # Exit the loop when i is 5
5    print(i)
6
7# Continue statement
8for i in range(10):
9    if i % 2 == 0:
10        continue  # Skip even numbers
11    print(i)  # Prints only odd numbers

1# Simple function
2def greet(name):
3    return f"Hello, {name}!"
4
5# Call the function
6message = greet("Python Learner")
7print(message)
8
9# Function with default parameter
10def greet_with_time(name, time="morning"):
11    return f"Good {time}, {name}!"
12
13print(greet_with_time("Alice"))
14print(greet_with_time("Bob", "evening"))

1# Lambda (anonymous) function
2multiply = lambda x, y: x * y
3print(multiply(5, 3))  # Outputs: 15
4
5# Lambda with built-in functions
6numbers = [1, 2, 3, 4, 5]
7squared = list(map(lambda x: x**2, numbers))
8print(squared)  # Outputs: [1, 4, 9, 16, 25]

1# *args for variable number of arguments
2def sum_all(*args):
3    return sum(args)
4
5print(sum_all(1, 2, 3, 4, 5))  # Outputs: 15
6
7# **kwargs for variable keyword arguments
8def print_info(**kwargs):
9    for key, value in kwargs.items():
10        print(f"{key}: {value}")
11
12print_info(name="Alice", age=25, country="Wonderland")

1# Import the math module
2import math
3
4# Use functions from the module
5print(math.sqrt(16))  # Square root: 4.0
6print(math.pi)        # Pi: 3.141592653589793
7
8# Import specific functions
9from random import randint
10print(randint(1, 10))  # Random integer between 1 and 10
11
12# Import with alias
13import datetime as dt
14now = dt.datetime.now()
15print(now)

1# mymodule.py
2def greeting(name):
3    return f"Hello, {name}!"
4
5def add(a, b):
6    return a + b
7
8PI = 3.14159

1# main.py
2import mymodule
3
4print(mymodule.greeting("Python User"))
5print(mymodule.add(5, 3))
6print(mymodule.PI)

1pip install requests

1import requests
2
3response = requests.get("https://api.github.com")
4print(response.status_code)
5print(response.json())

1def celsius_to_fahrenheit(celsius):
2    """Convert Celsius to Fahrenheit."""
3    return (celsius * 9/5) + 32
4
5def fahrenheit_to_celsius(fahrenheit):
6    """Convert Fahrenheit to Celsius."""
7    return (fahrenheit - 32) * 5/9
8
9def main():
10    print("Temperature Converter")
11    print("1. Celsius to Fahrenheit")
12    print("2. Fahrenheit to Celsius")
13    
14    choice = input("Enter your choice (1/2): ")
15    
16    if choice == '1':
17        celsius = float(input("Enter temperature in Celsius: "))
18        fahrenheit = celsius_to_fahrenheit(celsius)
19        print(f"{celsius}°C is equal to {fahrenheit:.2f}°F")
20    elif choice == '2':
21        fahrenheit = float(input("Enter temperature in Fahrenheit: "))
22        celsius = fahrenheit_to_celsius(fahrenheit)
23        print(f"{fahrenheit}°F is equal to {celsius:.2f}°C")
24    else:
25        print("Invalid choice")
26
27if __name__ == "__main__":
28    main()

1python temp_converter.py

1class Person:
2    # Class attribute
3    species = "Homo sapiens"
4    
5    # Constructor method
6    def __init__(self, name, age):
7        # Instance attributes
8        self.name = name
9        self.age = age
10    
11    # Instance method
12    def introduce(self):
13        return f"Hi, I'm {self.name} and I'm {self.age} years old."
14    
15    # Instance method
16    def celebrate_birthday(self):
17        self.age += 1
18        return f"Happy Birthday! Now I'm {self.age} years old."
19
20# Create objects of the Person class
21alice = Person("Alice", 25)
22bob = Person("Bob", 30)
23
24# Access attributes and call methods
25print(alice.name)                # Alice
26print(bob.age)                   # 30
27print(alice.species)             # Homo sapiens
28print(bob.introduce())           # Hi, I'm Bob and I'm 30 years old.
29print(alice.celebrate_birthday()) # Happy Birthday! Now I'm 26 years old.

1class Student(Person):
2    # Constructor method
3    def __init__(self, name, age, student_id):
4        # Call the parent class constructor
5        super().__init__(name, age)
6        self.student_id = student_id
7    
8    # Override the introduce method
9    def introduce(self):
10        return f"Hi, I'm {self.name}, a student with ID {self.student_id}."
11    
12    # New method specific to Student
13    def study(self, subject):
14        return f"{self.name} is studying {subject}."
15
16# Create a Student object
17charlie = Student("Charlie", 20, "S12345")
18
19# Access attributes and call methods
20print(charlie.name)        # Charlie
21print(charlie.student_id)  # S12345
22print(charlie.introduce()) # Hi, I'm Charlie, a student with ID S12345.
23print(charlie.study("Python"))  # Charlie is studying Python.