Python tutorial - #3 (Docstrings and Data-Type)

Docstrings = If we write string inside triple single quote (‘’’----‘’’) or triple double quote (“””----“””) and if these strings are written as first statements in a module, function, class or a method. Then these strings are called Documentation strings or simply Docstrings. These strings are useful to create an A.P.I documentation file from python program, An A.P.I (Application Programming Interface) documentation file is a text file or HTML file that contains the description of all features of software or product. When software is created it is the duty of programmer to create docstrings file in which they explain each and every class, Module, function etc. properly. It helps the user of the product (software) to use this smoothly.

Representing Binary, Octal and Hexadecimal number.

➠In python, Binary number are represented by adding 0 (zero) B or 0 (zero) b as prefix to each binary number.

Example: - 0B11001, 0b00101 etc.

                         Octal number in python are represented by adding 0 (zero) O or 0 (zero) o as prefix to each octal number. Example: - 0O12364, 0o12523, etc.

                                      And at last, Hexadecimal number are represented by adding o (zero)X or 0 (zero)x as prefix to each number. Example: - 0x11fb9, 0XA180, etc.

 Program - #1

Datatype Conversion

Changing of data from one datatype to another are called datatype conversion.

  Program- #2

Bool datatype = Bool datatype represent Boolean value. There are two Boolean values ---True and False. Python internally represents True as 1 and False as 0.

Program- #3

➢Here, there is a comparison between n1 (25) and n2 (21) in which it returns True in fourth line. thus, it execute the fifth line object. If fourth line returns False, then else statement executes. Observe this in the given program.

Program - #4

Literals in python:--

Literals are the value that stored in variable of a program.

    ⇨ Here, '21' is a literal value.

There are three types of literal:-

a) Numeric literal

    ⇨ Here, 1222 is a numeric literal

b) Boolean literal

c) String literal

    ⇨ Here, 'Hello World' is a string literal

Escape character

Escape character are useful to perform a different task. At first, observe the given some important escape characters.

Program - #5

Determining the datatype of a variable

To know, the datatype of variable or object we can use type() function.

Program - #6

Program - #7

User defined datatype = the datatype which are created by the programmers are called user-defined datatype. An Array, class, module are some examples of user-defined datatype.

Constant in Python

A constant is similar to a variable but its value cannot be modified or changed in the course of the program execution.

For example: - In Mathematics value of ‘Pi’  is always  22/7 and it is not possible to changed them. Constant in Python are same as.

Identifiers

An identifier is a name the is given to a variable or function or class etc.

Example:- num = 67
               ⇨  Here, 'num' is an Identifier
                 
                 str = 'Hello world'
               ⇨  Here, 'str' is also an Identifier

➠Identifier can include letters, numbers and the underscore character(_) They should always starts with a non numeric characters. Special symbols such as ?,#,$,% and @ are not allowed in identifier.

Note  Python is a case sensitive programming language, it means capital letters and small letters are identified separately by python.

Example – 'num' and 'Num' are treated as different names and hence represents different variables.