Lesson 2 of 13

Variables and data types

A variable is a name that refers to a value in memory. You create it with =, which means “store”, not “equals”.

PYTHON

name = "Sara"
age = 21
gpa = 4.5
is_mis = True
print(name, age, gpa, is_mis)
print(type(age), type(gpa), type(name), type(is_mis))

whole number	int → 21, -5, 0
decimal number	float → 4.5, 0.15
text	str → "Sara", 'IT'
true / false	bool → True, False

Sometimes a value is text but you need a number, like data read from a file. Convert with int(), float() and str().

PYTHON

price = "4800"
qty = 3
total = int(price) * qty
print(total)
print("Total: " + str(total))

Watch outVariable names use letters, digits and _, and can't start with a digit. Python convention is lowercase with underscores, like total_price.

Variables and data types

Exercises