Python Data Types

What Are Data Types?

In programming, a data type tells Python what kind of information a value represents and what operations are allowed on it. For example, you can multiply two numbers, while adding two strings joins text together.

For Python fundamentals, these four built-in types are essential:

Checking Types with type()

Whenever you are unsure what type a variable holds, pass it to the built-in type() function.

name = "Python"
lessons = 9
rating = 4.9
is_beginner_friendly = True

print(type(name))
print(type(lessons))
print(type(rating))
print(type(is_beginner_friendly))

<class 'str'>
<class 'int'>
<class 'float'>
<class 'bool'>

Mixing Types Carefully

Notice how quotes change the data type completely! "25" (with quotes) is a string, whereas 25 (without quotes) is an integer.

• "25" + "5" joins two strings into "255".
• 25 + 5 adds two integers into 30.
• "25" + 5 causes a TypeError because Python will not guess whether you want text joining or math addition.

age = 15
print("Age: " + age)

age = 15
print("Age: " + str(age))

Type Conversion (Casting)

When you need to change a value from one type to another, Python provides built-in conversion functions:

• int(x) — Converts a whole-number string or truncates a float into an integer.
• float(x) — Converts an integer or numeric string into a decimal number.
• str(x) — Converts numbers or booleans into text strings.
• bool(x) — Converts a value into True or False.

text_num = "18"
whole = int(text_num)
decimal = float(whole)

print(whole + 2)
print(decimal)
print("Value is " + str(whole))

20
18.0
Value is 18

Quick Check

Chapter Summary

• Python's core beginner data types are str (text), int (whole numbers), float (decimal numbers), and bool (True/False).
• Use type(value) to check any value's data type.
• Use int(), float(), str(), and bool() to convert between types explicitly.