Python: Basics

Python is a popular high-level programming language that is easy to learn and widely used in data analysis, machine learning, web development, and many other fields.

Defining Variables

In Python, we can define a variable and assign a value to it using the “=” operator. For example:

x = 10

Here, we’ve defined a variable x and assigned it the value of 10.

Performing Operations

We can also perform mathematical operations on variables:

y = 5
z = x + y

Here, we’ve defined a variable y and added it to x to create a new variable z.

Expressions

Expressions are combinations of operators and operands that can be evaluated to produce a value.

Python allows us to use expressions to perform operations on variables. For example:

a = 2
b = 3
c = a * b + 1

Here, we’ve defined three variables: a, b, and c. We’ve used the * operator to multiply a and b, and then added 1 to the result.

Expressions can also include functions:

import math
d = math.sqrt(a**2 + b**2)

Here, we’ve imported the math module and used the sqrt() function to calculate the square root of a^2 + b^2.

product = x * y
quotient = x / y

# Print statements
print("x =", x)
print("y =", y)
print("x + y =", sum)
print("x - y =", difference)
print("x * y =", product)
print("x / y =", quotient)

x = 10
y = 5
z = x + y
print(z)

This code will create two variables, x and y, assign them the values 10 and 5, respectively, and then add them together to create a new variable z with the value 15. Finally, the code prints the value of z.

Statements

In Python, a statement is a line of code that performs an action or task.

Statements are the smallest unit of code that can be executed and they represent an action or command. Each statement performs a specific task, such as defining a variable, calling a function, or creating a loop.

x = 10
print("Hello, world!")
def add_numbers(a, b):
    return a + b

In the above example, the first line (x = 10) is a statement that assigns the value 10 to the variable x. The second line (print(“Hello, world!”)) is a statement that prints the message “Hello, world!” to the console. The third line defines a function add_numbers that takes two arguments and returns their sum.

Statements vs Expressions

Some expressions can be statements, such as an assignment expression, which assigns a value to a variable.

However, not all statements are expressions. For example, a print statement does not evaluate to a value and cannot be used as part of an expression.

Script

A Python script is simply a collection of statements executed in order to achieve a desired outcome.