Keywords in Python are special reserved words that are part of the language itself. They define the rules and structure of Python programs which means you cannot use them as names for your variables, functions, classes or any other identifiers.
Getting List of all Python keywords
We can also get all the keyword names using the below code.
import keyword
print("The list of keywords are : ")
print(keyword.kwlist)
Output
The list of keywords are:
['False', 'None', 'True', 'and', 'as', 'assert', 'async', 'await', 'break', 'class', 'continue', 'def', 'del', 'elif', 'else', 'except', 'finally', 'for', 'from', 'global', 'if', 'import', 'in', 'is', 'lambda', 'nonlocal', 'not', 'or', 'pass', 'raise', 'return', 'try', 'while', 'with', 'yield']
Identify Python Keywords
Ways to identify Python Keywords are:
- With Syntax Highlighting: Most of IDEs provide syntax-highlight feature. You can see Keywords appearing in different color or style.
- Look for SyntaxError: This error will encounter if you have used any keyword incorrectly. Keywords can not be used as identifiers like variable or a function name.
Keywords as Variable Names
If we attempt to use a keyword as a variable, Python will raise a SyntaxError. Let's look at an example:
for = 10
print(for)
Output
Hangup (SIGHUP)
File "/home/guest/sandbox/Solution.py", line 1
for = 10
^
SyntaxError: invalid syntax
Let's categorize all keywords based on context for a more clear understanding.
| Category | Keywords |
|---|---|
Value Keywords | |
| Operator Keywords | and, or, not, is, in |
Control Flow Keywords | if, else, elif, for, while, break, continue, pass, try, except, finally, raise, assert |
| Function and Class | def, return, lambda, yield, class |
| Context Management | with, as |
| Import and Module | import, from |
| Scope and Namespace | global, nonlocal |
| Async Programming | async, await |
Keywords vs Identifiers
| Keywords | Identifiers |
|---|---|
| Reserved words in Python that have a specific meaning. | Names given to variables, functions, classes, etc. |
| Cannot be used as variable names. | Can be used as variable names if not a keyword. |
| Examples: if, else, for, while | Examples: x, number, sum, result |
| Part of the Python syntax. | User-defined, meaningful names in the code. |
| They cannot be redefined or changed. | Can be defined and redefined by the programmer. |
Variables vs Keywords
| Variables | Keywords |
|---|---|
| Used to store data. | Reserved words with predefined meanings in Python. |
| Can be created, modified, and deleted by the programmer. | Cannot be modified or used as variable names. |
| Examples: x, age, name | Examples: if, while, for |
| Hold values that are manipulated in the program. | Used to define the structure of Python code. |
| Variable names must follow naming rules but are otherwise flexible. | Fixed by Python language and cannot be altered. |
