Python Basics for Absolute BeginnersLesson 2 of 59 min read

Python Variables, Types and Input

Use variables, strings, integers and floats, read user input and convert it to numbers with int().

In Lesson 1 you printed text and numbers directly. Real programs need to remember things: a name, a score, a price. That’s what variables are for. In this lesson you’ll create variables, learn the three basic data types and write a program that talks back to the user.

Variables: names for values

A variable is a name that refers to a value. You create one with =:

name = "Aisha"
age = 19
print(name)
print(age)

Read = as “is set to”, not “equals”. The line age = 19 means “set age to 19”. You can change it later:

score = 0
score = score + 10
print(score)   # 10

The second line takes the current value of score (0), adds 10 and stores the result back in score.

Naming rules: variable names can contain letters, digits and underscores, but can’t start with a digit or contain spaces. By convention, Python programmers use lowercase words joined by underscores, such as total_price or first_name. Names are case-sensitive, so Score and score are different variables.

Three basic types

Every value in Python has a type. You can check it with type():

>>> type("hello")
<class 'str'>
>>> type(42)
<class 'int'>
>>> type(3.5)
<class 'float'>

Type	Name	Examples
str	string (text)	"hello", '42', ""
int	integer (whole number)	0, 7, -3
float	decimal number	3.5, 0.1, -2.0

Types matter because they decide what operations do:

print(3 + 4)       # 7     (int + int adds)
print("3" + "4")   # 34    (str + str joins)
print("ha" * 3)    # hahaha

And some combinations don’t work at all:

print("Age: " + 19)

TypeError: can only concatenate str (not "int") to str

Python won’t guess whether you meant to join text or add numbers. You need to convert one side, for example with str(19).

f-strings: the easy way to mix text and values

Instead of joining pieces with +, put an f before the quotes and write variables inside curly brackets:

name = "Aisha"
age = 19
print(f"{name} is {age} years old.")

Aisha is 19 years old.

f-strings convert values to text automatically and are the most readable option in modern Python.

Getting input from the user

The input() function shows a prompt, waits for the user to type something and press Enter, then gives you what they typed:

name = input("What's your name? ")
print(f"Nice to meet you, {name}!")

There’s one important catch: input() always returns a string, even if the user types a number.

age = input("How old are you? ")
print(age + 1)   # TypeError!

To do maths with it, convert it with int() (for whole numbers) or float() (for decimals):

age = int(input("How old are you? "))
print(f"Next year you'll be {age + 1}.")

If the user types something that isn’t a number, like nineteen, int() raises a ValueError. That’s fine for now. You’ll learn to handle it with a loop in Lesson 3.

Practice: a simple tip calculator

Put it all together:

# Tip calculator
bill = float(input("Bill amount: "))
percent = int(input("Tip percent (e.g. 15): "))

tip = bill * percent / 100
total = bill + tip

print(f"Tip: {tip:.2f}")
print(f"Total: {total:.2f}")

If you enter 40 and 15, it prints:

Tip: 6.00
Total: 46.00

The :.2f inside the curly brackets formats a number with exactly two decimal places, which is handy for money.

Key takeaways

• A variable is a name that refers to a value; = sets it.
• The basic types are str (text), int (whole numbers) and float (decimals).
• The same operator can behave differently by type: + adds numbers but joins strings.
• f-strings like f"Hi {name}" are the easiest way to mix text and values.
• input() always returns a string; convert it with int() or float() before doing maths.

Source checked: the official Python Tutorial, section “An Informal Introduction to Python”.

In Lesson 3 your programs will start making decisions and repeating actions.