Python Data Types

A data type represents the type of data stored into a variable or memory. The data types which are already available in Python language are called built-in data types. The data types which can be created by the programmers are called User-defined data types.

The built-in data types are of five types:

  • None Type
  • Numeric Type
  • Boolean Type
  • Sequences
  • Sets
  • Mappings

None Type

In Python, the 'None' datatype represents an object that does not contain any value. In languages like Java, it is called 'null' object. But in Python, it is called 'None' object.

In a Python program, maximum of only one 'None' object is provided. One of the uses of 'None' is that it is used inside a function as a default value of the arguments. When calling the function, if no value is passed, then the default value will be taken as 'None'. If some value is passed to the function, then that value is used by the function. In Boolean expressions, 'None' datatype represents 'False'.

Numeric Type in Python

The numeric types represent numbers. There are three sub types:

  • int
  • float
  • complex

int Datatype

The int datatype represents an integer number. An integer number is a number without any decimal point or fraction part. For example, 200, -50, 0, 9888998700, etc. are treated as integer numbers. Now, let's store an integer number -57 into a variable 'a'.

a = -57

Here, 'a' is called int type variable since it is storing -57 which is an integer value. In Python, there is no limit for the size of an int datatype. It can store very large integer numbers conveniently.

float Datatype

The float datatype represents floating point numbers. A floating point number is a number that contains a decimal point. For example, 0.5, -3.4567, 290.08, 0.001 etc. are called floating point numbers. Let's store a float number into a variable 'num' as:

num = 55.67998

Here num is called float type variable since it is storing floating point value. Floating point numbers can also be written in scientific notation where we use 'e' or 'E' to represent the power of 10. Here 'e' or 'E' represents 'exponentiation'. For example, the number 2.5 104 is written as 2.5E4. Such numbers are also treated as floating point numbers.

For example

x = 22.55e3

Complex Datatype

A complex number is a number that is written in the form of a + bj or a + bJ. Here, 'a' represents the real part of the number and 'b' represents the imaginary part of the number. The suffix 'j' or 'J' after 'b' indicates the square root value of -1. The parts 'a' and 'b' may contain integers or floats.

For example

3+5j,

-1-5.5J,

0.2+10.5J

are all complex numbers

See the following statement:

c1 = -1-5.5J

Representing Binary, Octal and Hexadecimal Numbers

A binary number should be written by prefixing 0b (zero and b) or 0B (zero and B) before the value.

For example, 0b110110, 0B101010011 are treated as binary numbers.

Hexadecimal numbers are written by prefixing 0x (zero and x) or 0X (zero and big X) before the value, as 0xA180 or 0X11fb91 etc.

Similarly, octal numbers are indicated by prefixing 0o (zero and small o) or 0O (zero and then O) before the actual value. For example, 0O145 or 0o773 are octal values.