Programs process data, which is represented by objects. In Python everything is an object: variables, literals, functions, classes, modules.
In Python we don’t need to (and actually can’t) explicitly declare the data type of a variable. The type is determined at runtime. This feature is known as dynamic typing.
Table of Contents
Data Types
There are 3 main kinds of objects:
1) built-in objects – provided by Python
2) objects from extension libraries
3) custom objects – created in the application by the programmer
We’re going to discuss the built-in data types first, also referred to as built-ins. We’re going to talk about the other types later in the course.
Built-In Data Types
Let’s start with the built-in data types. These are types you get out of the box. Here belong:
– numerics
– sequences
– mappings
– files
– instances
– exceptions
These are just general names, or categories. Each of them contains several actual types. Let’s have a look at some of them, starting with numerics.
Built-In Numeric Types
Here we have three types:
– integers (ints)
– floating-point numbers (floats)
– complex numbers
Sequential Data Types
As far as sequences are concerned, you already know strings. But strings are by far not the only sequences in Python.
This category includes:
– strings
– byte sequences
– byte arrays
– lists
– tuples
– range objects
To work with data we also need operators. Let’s have a look at some of the commonly used ones.
Operators
Operators are the constructs used to manipulate operands.
For example in:
3 * 5 – 1
3, 5 and 1 are operands, whereas * and – are operators.
There are many types of operators:
– Arithmetic Operators
– Comparison Operators
– Assignment Operators
– Membership Operators
– Logical Operators
– Bitwise Operators
– Identity Operators
We’re going to explore data types and operators in the following sections of the course, starting with numbers, which are the subject of the next section.