Difference between keyword and identifier in python
Every language has its vocabulary similarly; every
programming language comes with its set of keywords. Almost all high-level
programming languages contain a set of keywords. Some of the most common
keywords used in almost all high-level programming languages are: if, else,
while, for, break, etc. These keywords are also known as reserved keywords in
python. Keywords have some predefined meaning in the programming language. We
cannot assign any value to keywords. For storing the value, we generally use
variables. Also, we give names to the entities like class, functions, and variables;
these names are known as identifiers. In this article, we will deep dive into
the concept of keywords and identifiers in python programming.
Keywords (Reserved words)
As python is a case sensitive language, reserved words in
python are also case sensitive. Keywords are also called reserved keywords in
python because they have a predefined meaning and are strictly used for a
specific purpose. We cannot assign a new value to the reserved words. The most
important thing about reserved words is that they should be used in the given
case. If we change the cases of the reserved words, then it does not follow the
predefined meaning. It will not be considered a reserved word anymore. In the
diagram given below, we can see the list of reserved words used in Python.
Python contains 33 reserved words. Some of them are int, float, import, if,
elif, True, False, None, etc. We can notice that all the keywords are in
lowercase except None, True, and False. Let’s have a look at few
False: these are the Boolean
values in python. The result of the logical operation is indicated by any
one of these values.
or, not: these are logical
operators in python. And the result of these operators is always a Boolean
elif, else: these keywords are used in the decision control
for:these keywords are used
in a loop control structure
continue: these keywords are used within the loop control
structure to terminate the execution of the loop or to terminate the
execution of the current iteration of the loop
keyword is used to create a user-defined class
keyword is used to create a user-defined function
except, raise, finally: these
keywords are used in exception handling to handle the exception that
occurred during the execution of the program
import: these keywords are used to import any in-built
module of python programming to your current namespace
keyword is used within the function if you want to access the variable
defined inside the function from outside the function.
So these are some commonly used reserved keywords in python.
Let’s see an example of keywords:
In the given example we have used the following keywords:
int, for, in, def, if, or, else, True, False
Now let’s start with the concept of Identifiers.
Names given to the entities like variables, class, and function are commonly known
as identifiers in python. We cannot use keywords as identifiers
otherwise program will throw an error. There are some rules for writing identifiers in python. They are as follow:
identifier can have alphanumeric characters only; no special symbol except
underscore ( _ ) is allowed. E.g. student_name1 is a valid identifier name
is a case sensitive language; that’s different cases have different
meanings. E.g. name and NAME will be considered as different identifiers.
between the identifier is not allowed. E.g. student name is not a valid
variable name. Instead, you can write it as a student_name
identifier should always start with a letter or an underscore. You cannot
start an identifier with a number. E.g. name1 or _name1 is a valid
variable name, but 1name is not a valid identifier in python
identifier can be of any length; there is no limitation about it.
Let’s see examples of identifiers in python:
In the given example, the following are the valid
identifier in python: a and b (these are the names given to lists), f1 (this is
a name given to a function)
Difference between keyword and
identifier in python
The given table indicates the difference between keyword
and identifier in python:
In this article, we have learned about keywords and
identifiers in python. Also, we have learned about the difference between
keyword and identifier in python. Python is a case sensitive language, and
keywords are also case-sensitive. Keywords in python have a predefined meaning,
and they are created for a specific purpose. Names given to class, variables,
and function are Identifiers. We cannot assign a keyword as an identifier.
There are some rules to be followed by the programmer when naming or writing
valid identifiers in python. So, this is all about keywords and identifiers in
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