Python Keywords and Identifiers, keywords (reserved words in Python), and identifiers (names given to variables, functions, etc.).
Python keywords are also known as reserved words. Keywords are particular words that act as a key to a code. These are predefined words by Python, so they cannot be used as identifiers.
Identifiers in Python are symbolic names used for identification. They can be a class name, variable name, method name, function name, and more.
Note: Python keywords or reserved words can not be used as an identifier.
Python keywords or reserved words are particular words that act as a key to a code. We have “keywords” in every programming language, Python keywords are small letters, and Python is a case-sensitive language.
|and||A logical operator|
|as||To create an alias|
|break||To break out of a loop|
|class||To define a class|
|continue||To continue to the next iteration of a loop|
|def||To define a function|
|del||To delete an object|
|elif||Used in conditional statements, same as else if|
|else||Used in conditional statements|
|except||Used with exceptions, what to do when an exception occurs|
|False||Boolean value, result of comparison operations|
|finally||Used with exceptions, a block of code that will be executed no matter if there is an exception or not|
|for||To create a for loop|
|from||To import specific parts of a module|
|global||To declare a global variable|
|if||To make a conditional statement|
|import||To import a module|
|in||To check if a value is present in a list, tuple, etc.|
|is||To test if two variables are equal|
|lambda||To create an anonymous function|
|None||Represents a null value|
|nonlocal||To declare a non-local variable|
|not||A logical operator|
|or||A logical operator|
|pass||A null statement, a statement that will do nothing|
|raise||To raise an exception|
|return||To exit a function and return a value|
|True||Boolean value, result of comparison operations|
|try||To make a try…except statement|
|while||To create a while loop|
|with||Used to simplify exception handling|
|yield||To end a function, returns a generator|
An identifier is a name given to entities like class, functions, variables, etc. It helps to differentiate one entity from another.
Rules for writing identifiers
1. Identifiers can be a combination of letters in lowercase (a to z) or uppercase (A to Z) or digits (0 to 9) or an underscore _. Names like myClass, var_1 and print_this_to_screen, all are valid example.
2. An identifier cannot start with a digit. 1variable is invalid, but variable1 is a valid name.
3. Keywords cannot be used as identifiers.
global = 1
SyntaxError: invalid syntax
4. We cannot use special symbols like !, @, #, $, % etc. in our identifier.
a@ = 0
SyntaxError: invalid syntax
5. An identifier can be of any length.