Python Basics - Olevel/IGCSE

Python is an extensively used high-position programming language that’s simple to learn and easy to read. It’s a popular choice for newcomers because it emphasizes law readability and ease of use. In this composition, we’ll go over the basics of Python programming and cover the crucial generalities that you will need to get started.

How to install Python?

First thing first, you need to install Python on your device. To install python on your device follow the steps below:

Head over to Python.org
Click on Downloads
Click on Install and follow the installation steps.

IDE editors for Python

There are may IDE editors which can be used to write Python code. When installing Python you do get a built-in editor, but it is not really friendly so, here i will go through some IDE editors which you can use for Python.

Offline Editors

Online Editors

Before we begin

Before we begin, remember that Python is a “tab” sensitive language. Unlike other languages such as JavaScript, Java, C, C++, C#, which has extensive use of colons, commas, semi-colons. Python rely on tabs and spacing. It enters and exits loop, parameters, global and local variables using tabs and spacing.

Variables and Constants:

Variables are used to store data in a program, and constants are values that don’t change. In Python, you can declare a variable by assigning a value to it. Same is the case with constants. Declaring variables and constants in Python aren’t that much of a difference. Here is an example:

# Declare a variable
x = 5

# Declare a constant
PI = 3.14

Data Types:

Python supports several data types, including integers, floating-point numbers, characters, strings, and Boolean values here are some example on how to use them:

# Integer
x = 5

# Float
y = 3.14

# Character
z = 'a'

# String
name = 'John Doe'

# Boolean
is_valid = True

Input and Output:

Well we all are not kids anyone to not know what Input and Output means? The input function is used to receive user input, and the print function is used to display output on the screen.

# Receive user input
name = input("What is your name? ")

# Display output
print("Hello, " a+ name + "!")

Different types of Inputs:

In the given example we are allowing any type of data to be entered. If we want to restrict the type of data being entered we can:

#string
example = str(input("Please enter your name: "))
#number (float)
num = float(input("Please enter a number: "))
#number (int)
num = int(input("Please enter a number: "))

Sequence, Selection, and Iteration:

These are fundamental programming concepts that allow you to control how your program is executed. The order in which statements are executed is referred to as the sequence, whereas selection is used to make decisions based on conditions and iteration is used to repeat a set of statements.

# Sequence
x = 5
y = 10
z = x + y

# Selection
if z > 10:
  print("Z is greater than 10")
else:
  print("Z is less than or equal to 10")

# Iteration
for i in range(10):
  print(i)

Arithmetic, Logical, and Boolean Operators:

These operators are used to perform arithmetic, comparison, and logical operations in a program.

# Arithmetic
x = 5
y = 3
z = x + y
print(z)

# Comparison
x = 5
y = 3
print(x > y)

# Logical
is_valid = True
is_correct = False
print(is_valid and is_correct)

Procedures, Functions, and Parameters:

Procedures and functions are code blocks that can be called from other sections of a program. Variables that are passed into a function or procedure are known as parameters.

# Function with one parameter
def square(x):
  return x ** 2

# Function with two parameters
def add(x, y):
  return x + y

# Procedure with no parameters
def say_hello():
  print("Hello!")

Library Routines:

Python provides a vast collection of library routines that can be used to perform various tasks, such as working with files, performing mathematical operations, and interacting with the system.

Math Module: The math module provides functions for mathematical operations. For example:

import math

# square root
print(math.sqrt(25))  # Output: 5.0

# logarithm base 10
print(math.log10(100))  # Output: 2.0

# trigonometric functions
print(math.sin(math.pi/2))  # Output: 1.0

Random Module: The random module provides functions for generating random numbers. For example:

import random

# random integer between 1 and 10
print(random.randint(1, 10))

# random choice from a sequence
fruits = ['apple', 'banana', 'cherry']
print(random.choice(fruits))

Arrays:

Arrays are used to store multiple values in a single variable. In Python, you can declare one-dimensional and two-dimensional arrays.

# One-dimensional array
numbers = [1, 2, 3, 4, 5]

Using Arrays:

You can read and write values to an array using iteration and variables as indexes.

# Two-dimensional array
matrix = [
  [1, 2],
  [3, 4]
]

Files:

Storing data in a file is a common way to save and use data in a program. Python provides functions for opening, closing, reading, and writing to files.

# Open a file for writing
file = open("myfile.txt", "w")

# Write data to file
file.write("Hello, world!")

# Close the file
file.close()

# Open a file for reading
file = open("myfile.txt", "r")

# Read data from file
data = file.read()

# Close the file
file.close()

# Display data
print(data)

Python is an extremely powerful programming language that is widely used in web development, data analysis, and automation. Understanding Python’s fundamental concepts and syntax will allow you to start writing your own programs and exploring the language’s vast capabilities. Continue practising, and you’ll soon be able to call yourself a Python expert!

Python Basics made simple for beginners