Table of Contents
what are python identifiers with example :
An identifier is a simple concept which is used to identify entities. ( i.e. class, variables, functions,module or other object ) Identifier used to differentiate one entity from another entity. An identifier starts with an underscore (_), letter A to Z or small letter a to z or simply follow by zero or more letter and digits (0 to 9).
Python identifier simple example :
 |
| what are python identifiers |
- rollno.,
-
_sachin - and sachin
_sampradaare the identifiers.
# Basic examples on identifiers rollno = 1 print(rollno) _sachin = 5 print(_x) sachin_samprada = 143 print(sachin_samprada)
>> 1
>> 5
>> 143
which is valid identifier in python 3.10
There are different no. of rules that must need to be followed to create a python identifier.
- An identifier starts with an underscore (_), letter A to Z or small letter a to z or simply follow by zero or more letter and digits (0 to 9)
- sachin_SAMPRADA : contains all the valid character
- _: underscore is also valid identifier
- _sachin: it is valid to identifier can start with an underscore symbol
Some python Invalid Identifiers Example :
- 143: identifier cannot be only digit
- 143samprada: identifier cannot start with number
- sachin+samprada: the only special character is valid an underscore
- from: it is a reserved keyword
How to check if a String is a Valid Identifier in python? :
- Identifier name cannot begin with a digit or number.
- Python identifier cannot contain only digits or number.
- Identifier name can start with an underscore is valid.
- There is no any limit on the length of the identifier.
- Identifier name are case sensitive in nature.
- sachin143samprada: Identifier contain only letters and numbers
We can use python string identifier() Functions to check identifier name is valid or not. But, this method doesn’t take reserved keywords into consideration. So, we can use this function with keyword.iskeyword() to check if the name is valid or not.
print(“_”.fallinlove()) # True
print(“for”.inlove()) # True – wrong output(error)
print(“sahin”.inlove()) # True
print(“143sach”.isidentifier()) # False
list of the Python keywords :
...
help> keywords
Here is a list of the Python keywords. Enter any keyword to get more help.
False def if raise
None del import return
True elif in try
and else is while
as except lambda with
assert finally nonlocal yield
break for not
class from or
continue global pass
Things to must Remember :
- Multiple set of word can be separated using an underscore, like (fall_in_love)
- variable and variable later are not the same(i.e.Python is a case-sensitive language)