Data types

What you need to know about data types

Python can store different types of data
The basic types of data you’ll learn about first are:
- Strings
- Integers
- Floats
- Booleans
Python can do different operations based the data type
- like + to add numbers together

Basic Data Types

Your name, age, date of birth, and photo are different pieces of data. Data, and the variables that refer to them, are represented by different types.

Every programming language has data types, but the built-in types are different from one programming language to another. In Python, we have more than 10 built-in data types. Here are the 3 types we need in this lesson:

int (for integer)
- Represents integer numbers, like 1, 4, or 10
float (a floating-point number)
- Represents floating-point numbers, like 1.0, 4.32, or 10.189
- You might know these as ‘decimal’ numbers or fractions - numbers that have a dot separating the integer part from the fractional part.
str (for string)
- Stores text as character-based data like words, e.g., Hello World

These are called primitive types. Python can represent more complicated data using compound types like List and Dictionary, which are made out of the primitive types. We’ll learn about some of those in later lessons.

Python figures out the type automatically based on some rules:

numbers without a decimal point are treated as ints (like 10)
numbers with a decimal point are treated as floats (like 1.0)
text between quote marks is treated as strings (like "Hello" or '100.5')

There are more rules for other types, but we're skipping them for now.

Video: Data Types

Data Types

Every value in Python has a type, for example, string, float, and integer. You can find out what type a value is by using the type() function.

Strings

Strings are for representing text.

They look like this: "Kibo School", starting and ending with ", the double quote.

When you add them together with +, Python concatenates the strings. It sticks them together end to end, like this:

school_name = "Kibo"
print("I love " + school_name) # "I love Kibo"

They are called strings because they are a series (a ‘string’) of characters. The string "Kibo" is made of the characters 'K', 'i', 'b', 'o'.

Integers

Integers are for representing positive and negative whole numbers.

They look like numbers: 10, 9019, or -5

Python works like a calculator. It can do math with +, -, *, / and more.

10 + 5 # 15

value = 100
value + 10 # 110
value - 10 # 90
value * 10 # 1000
value / 10 # 10

Floats

Floats are for representing fractional numbers

They look like numbers with a decimal point: 10.5, 90.19, or -0.781

Python stores them differently from integers, so they show something different when you call type on them

TypeErrors

TypeError is a common error you get when the types don’t match, like if you tried to add a string and a number.

"Hello" + "5" # "Hello5"
"Hello" + 5 # TypeError

There are lots more Python types that we didn’t cover. You can look them up by using Google to find the Python documentation.

Question: What do you happens when you add a float and an integer? Try to guess the answer first, then try it out in the Python interpreter.

Programming 1