Token in Python

In a Python program, the smallest individual units are known as tokens. Python has 5 types of tokens. They are given below:

• Keywords
• Identifiers
• Literals
• Operators
• Punctuators

Keywords:

Keywords are the reserved words that have special meanings, and these meanings cannot be changed. Keywords serve as basic building blocks for program statements.

          Example: for, del, elif, else etc

Identifiers:

Identifiers refer to the names of variables, functions, class, module, or other objects. For naming an Identifier, there are basic rules that we must follow. These rules are given below:

• The identifier does not begin with a digit.

          For Example, 2num is an invalid Identifier name

• The first character of an identifier must be a letter(upper or lowercase) or an underscore, and the rest of the Identifier name can be underscored (‘_’), letter(uppercase or lowercase), or digits(0-9)

          For Example: a1, _A are valid Identifier names.

• Identifier names are case-sensitive.

          For Example, loan_amount, LOAN_AMOUNT are two different Identifier names.

• Punctuation characters such as $, @, and % are not allowed within the Identifier.

          For Example, salary%amount, aBabu Nanjajjar, %cash are invalid Identifier names.

Literals

Python Literals are defined as data that is given in a variable or constant. Python supports the  following literals:

String Literals:

A string Literal is a sequence of characters enclosed in quotes. The characters may be letters, numbers, special characters, and blank space.

We can use a string in the following ways in a Python program.

Using Single Quotes (‘): For example, a string can be written as ‘WELCOME’.

Using Double Quotes (“): Strings in double-quotes are the same as those in single quotes. Therefore ‘WELCOME’ is the same as “WELCOME”.

Using Triple Quotes (‘’’ ‘’’): We can specify multi-line strings using triple quotes. We can use as many single quotes and double quotes in a string within triple quotes.

For example, a multi-line string can be written as,

‘’’Good morning to all. “Welcome to the world of ‘programming’.“  Happy reading.’’’