Skip to content
# Data Types

How do we represent data in a computer?
All data inside of modern computers are stored
as a series of ones and zeros.
We call this binary data.
The ones and zeros are called binary digits
(or “bits” for short).
In modern computers, data are stored in small
blocks of eight bits called a “byte”.
We can combine two, four, eight, or more bytes together to create larger blocks of binary data.
However, the computer needs to understand
what each of these blocks of ones and zeros
represent – is it a word, a number, a date
and time, or something else?
This is where data types come into play not
to be confused with the “types of data” we
discussed previously.
A data type is an attribute of data that tells
the computer what a group of binary data represents.
They tell the computer how to interpret the
bits of data – either as a character, a
number, a date, or something else.
They determine what operations can be performed
on the data, like addition, subtraction, and
multiplication.
They specify how the data are stored and the
size of the data by the number of bytes they require.
And they instruct the computer on how to display
the data in a human-readable format.
For example:
We represent the letter A as a byte of binary
digits using a sequence containing a zero,
a one, five zeros, and a one.
We represent the digit one in binary as two
zeros, two ones, three zeros, and a one.
And we represent the percent symbol as two
zeros, a one, two more zeros, a one, a zero, and a one.
Essentially, we can represent anything that
can be typed into a computer as a sequence
of ones and zeros using data types.
In data science, there are two main divisions
of data types:
First, we have scalar data types, also known
as primitive data types, basic data types,
or built-in data types.
Scalar data types represent the most basic
building blocks of data by storing letters,
numbers, and symbols in a computer as binary
data.
Next, we have composite data types, also known
as aggregate data types, compound data types,
or more commonly, data structures.
Composite data types are composed of a set
of scalar data types.
They organize the scalar data types and provide
them with structure so that they can be worked
with as a collection of values.
We’re going to discuss both scalar data types,
followed by composite data types, next.