Python Keywords and Identifiers (Updated)

Let’s talk about Python keywords and identifiers. We recently also covered a complete tutorial on installing and setting up Python for beginners in this Python tutorial.

Python Keywords

Well simply, Python keywords are the words that are reserved. That means you can’t use them as name of any entities like variables, classes and functions.

So you might be thinking what are these keywords for. They are for defining the syntax and structures of Python language.

You should know there are 33 keywords in Python programming language as of writing this tutorial. Although the number can vary in course of time. Also keywords in Python is case sensitive. So they are to be written as it is. Here is a list of all keywords in python programming.

Python Keywords and Identifiers (Updated)

If you look at all the keywords and try to figure out all at once, you will be overwhelmed. So for now just know these are the keywords. We will learn their uses respectively. You can get the list of python keywords through python shell help.

List of All Python Keywords

and Logical operator
as Alias
assert For debugging
break Break out of
Python loops
class Used for defining
Classes in Python
continue Keyword used to continue with the Python loop by skipping the existing
def Keyword used for defining a function
del Used for deleting
objects in Python
elif Part of the if-elif-else
conditional statement in Python
else Same as above
except A Python keyword used to catch exceptions
FALSE Boolean value
finally This keyword is used to run a code snippet when no exceptions occur
for Define a
Python for loop
from Used when you need to import only a specific section of a module
global Specify a variable scope as global
if Used for defining an “if” condition
import Python keyword used to import modules
in Checks if specified values are present in an iterable object
is This keyword is used to test for equality.
lambda Create
anonymous functions
None The
None keyword
represents a Null value in PYthon
nonlocal Declare a variable with non-local scope
not Logical operator to negate a condition
or A logical operator used when either one of the conditions needs to be true
pass This Python keyword passes and lets the function continue further
raise Raises an exception when called with the specified value
return Exits a running function and returns the value specified
TRUE Boolean value
try Part of the
try…except statement
while Used for defining a
Python while loop
with Creates a block to make exception handling and
file operations
yield Ends a function and returns a generator object

Below is a simple example showing usage of if-else in python program.

var = 1;


When we run the above program, Python understands the if-else block because of fixed keywords and syntax and then do the further processing.

What are Python Identifiers?

Python Identifier is the name we give to identify a variable, function, class, module or other object. That means whenever we want to give an entity a name, that’s called identifier.

Sometimes variable and identifier are often misunderstood as same but they are not. Well for clarity, let’s see what is a variable?

What is a Variable in Python?

A variable, as the name indicates is something whose value is changeable over time. In fact a variable is a memory location where a value can be stored. Later we can retrieve the value to use. But for doing it we need to give a nickname to that memory location so that we can refer to it. That’s identifier, the nickname.

Rules for Writing Identifiers

There are some rules for writing Identifiers. But first you must know Python is case sensitive. That means Name and name are two different identifiers in Python. Here are some rules for writing Identifiers in python.

  1. Identifiers can be combination of uppercase and lowercase letters, digits or an underscore(_). So
    all are valid python identifiers.
  2. An Identifier can not start with digit. So while
    is valid,
    is not valid.
  3. We can’t use special symbols like !,#,@,%,$ etc in our Identifier.
  4. Identifier can be of any length.

Though these are hard rules for writing identifiers, also there are some naming conventions which are not mandatory but rather good practices to follow.

  1. Class names start with an uppercase letter. All other identifiers start with a lowercase letter.
  2. Starting an identifier with a single leading underscore indicates the identifier is private.
  3. If the identifier starts and ends with two underscores, than means the identifier is language-defined special name.
  4. While
    c = 10
    is valid, writing
    count = 10
    would make more sense and it would be easier to figure out what it does even when you look at your code after a long time.
  5. Multiple words can be separated using an underscore, for example

Here’s a sample program for python variables.

myVariable="hello world"



If you run the program, the output will be like below image.

Python Keywords and Identifiers (Updated)


So, that’s it for today. In the next tutorial, we will learn about Python Statements and Comments. Till then #happy_coding 🙂

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