Introduction
In any language, consider English, there would be a set of words that would give us a meaningful sentence when used together. Similarly, there are some words called Keywords and Identifiers used to write the code in programming languages. Keywords and identifiers together build the vocabulary for the programming language. Keywords are reserved words with specific meanings, while identifiers are names given to variables, labels, or classes in a program.
Let’s learn about the difference between Keyword and Identifier in detail.
Keyword Vs. Identifier: Explore the difference between Keyword and Identifier
There are two distinct concepts that are mainly used in Python, i.e., keywords and identifiers. There are lots of differences between these two. Let us understand them:
- Keywords are reserved words in Python with predefined meanings. On the other hand, identifiers are user-defined names used to identify variables, functions, classes, modules, etc.
- Keywords are used to define the structure and flow of the program. On the other hand, identifiers are used to represent variables, functions, classes, and other user-defined objects.
- Keywords are an integral part of the Python syntax and cannot be reassigned or redefined. On the other hand, identifiers can be assigned values, modified, and reused throughout the program.
- Keywords have predefined meanings in Python, and as such, they cannot be used as identifiers. On the other hand, identifiers must follow certain rules and conventions in Python. They can consist of letters (a-z, A-Z), digits (0-9), and underscores (_). However, they cannot start with a digit.
What is a Keyword?
Keywords are one of the important things in Python. They are reserved words that have predefined meanings. They are part of the Python language syntax. We cannot use keywords as identifiers (variable names, function names, etc.). They serve specific purposes in the language. Keywords are used to define control structures, data types, and other elements in Python code.
There are some examples of keywords in Python:
- if: It is used for conditional statements.
- else: It is used in conjunction with if to define alternative branches in conditional statements.
- for: It is used for iterating over a sequence (such as a list or string).
- while: It is used to create a loop that continues until a certain condition is met.
- def: It is used to define a function.
- class: It is used to define a class.
- import: It is used to import modules or specific objects from modules.
- return: It is used to specify the return value of a function.
- True, or False: They represent boolean values.
- and, or, not: They are used for logical operations.
- try, except, finally: They are used for exception handling.
What is an Identifier?
Identifier is also an important concept in Python. It is a user-defined name. It is used to identify variables, functions, classes, modules, or other objects. It serves as a label or reference within the code. They play a crucial role in creating and accessing different elements in a Python program.
They are some important points about identifiers in Python:
- It can consist of letters (both uppercase and lowercase), digits, and underscores (_).
- We cannot use a digit in starting. It must begin with a letter or an underscore(_).
- Python is case-sensitive, so identifiers with different casing are treated as distinct.
- It should follow naming conventions to enhance code readability. We can use lowercase letters for variables and functions. We can use capitalized words for classes.
- Some examples of valid identifiers are counter, total_amount, calculate_average, and Ninja.
- Some examples of invalid identifiers are 3ninjanames, if, and for.
Difference between Keyword and Identifier
Keyword | Identifier |
|---|---|
| Keywords are the reserved words with a special meaning. | Identifiers are the user-defined names of variables, functions, etc. |
| They are written in lower case except for True, False, and None. | Need not be written in lowercase. |
| It helps to identify a specific property that exists within Python. | It identifies the name of the particular entity. |
| Contains only letters | Contains letters, underscore, and digits. |
| Example:- or, raise, pass | Example:- maxCount, minNum1, etc |
Frequently Asked Questions
What are the two types of identifiers?
The two types of identifiers are internal identifiers and external identifiers. The internal identifier is used for the local scope, whereas the external identifiers are used in the global scope for external linkage.
Is printf a keyword or identifier?
'printf' is an identifier. It is the name of the function which receives parameters for displaying the output. It is an identifier name for a function.
Give some examples of identifiers?
flag, count_3, add_, sum1, etc. are examples for identifiers.
Give some examples for keywords?
if, not, assert, yield, etc., are examples for keywords.
What is the difference between a keyword and an identifier in Python?
A keyword in Python is a reserved word that has a specific meaning and purpose in the language, such as "if", "else", or "while". An identifier is a name given to a variable, class, function, or other user-defined entity in the code.
Conclusion
In this blog, difference between keyword and identifier was covered in detail, along with examples. This blog also included the differences between Python keywords and identifiers, rules for naming identifiers, use of isidentifier() method, and FAQs related to Python keywords and identifiers.
Don't stop here. Check out our Python guided path to learn Python from Scratch.
We hope you found this blog useful. Feel free to let us know your thoughts in the comments section.
