Farhad Rahimi Klie

Posted on Dec 5

Python for Beginners and Intermediate Developers — A Complete Guide

#python #code #programming #webdev

Python is one of the most widely used programming languages in the world. Its clean syntax, massive ecosystem of packages, and versatility make it perfect for beginners and powerful enough for intermediate and advanced developers.

In this article, you will learn Python step-by-step—from fundamentals to intermediate-level concepts—with fully explained examples you can copy, paste, and run.

Why Python?

Python is popular because it is:

Beginner-friendly
Easy to read and write
Used in web development, data science, AI/ML, automation, DevOps, game development, and more
Supported by a huge community
Available on all major operating systems

Let’s begin with the essentials.

1. Python Basics

1.1 Variables

A variable stores data.

name = "Farhad"
age = 20
is_active = True

print(name)
print(age)
print(is_active)

Explanation:

Strings use quotes.
Integers do not use quotes.
Boolean values start with a capital letter: True or False.

1.2 Data Types

Python has several built-in data types:

x = 10              # int
pi = 3.14           # float
name = "Python"     # str
is_ok = True        # bool
items = [1, 2, 3]   # list
points = (4, 5)     # tuple
user = {"name": "Ali", "age": 25}  # dict

1.3 Input From User

username = input("Enter your name: ")
print("Hello, " + username)

1.4 Conditional Statements (if, elif, else)

age = 18

if age > 18:
    print("You are an adult.")
elif age == 18:
    print("You just turned 18!")
else:
    print("You are under 18.")

2. Working With Loops

2.1 For Loop

for i in range(5):
    print("Number:", i)

Explanation:
range(5) generates numbers 0 to 4.

2.2 While Loop

count = 1

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

3. Functions

Functions help you avoid repeating code.

def greet(name):
    print("Hello,", name)

greet("Farhad")
greet("Klie")

4. Lists, Tuples, and Dictionaries

4.1 Lists

fruits = ["apple", "banana", "orange"]
fruits.append("mango")

print(fruits)

4.2 Tuples (immutable)

point = (10, 20)
print(point[0])

4.3 Dictionaries

person = {
    "name": "Farhad",
    "age": 20
}

print(person["name"])

5. Intermediate Python Concepts

Let’s move to the next level.

5.1 List Comprehension

A faster, cleaner way to create lists.

numbers = [1, 2, 3, 4, 5]
squares = [x * x for x in numbers]

print(squares)

5.2 Lambda Functions

Small, anonymous functions.

square = lambda x: x * x
print(square(5))

5.3 Map, Filter, Reduce

map()

nums = [1, 2, 3]
doubled = list(map(lambda x: x * 2, nums))
print(doubled)

filter()

nums = [1, 2, 3, 4, 5, 6]
even = list(filter(lambda x: x % 2 == 0, nums))
print(even)

5.4 Error Handling (try/except)

try:
    number = int(input("Enter a number: "))
    print("You entered:", number)
except ValueError:
    print("Invalid number. Please enter digits only.")

5.5 Working With Files

Write to a file

with open("data.txt", "w") as f:
    f.write("Hello, Python!")

Read from a file

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

5.6 Object-Oriented Programming (OOP)

Class and Object Example

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

    def introduce(self):
        print(f"My name is {self.name}, and I am {self.age} years old.")

p1 = Person("Farhad", 20)
p1.introduce()