Python Keywords: An Introduction :
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Python keywords are reserved words with specific functions and restrictions in the language. Currently, Python has thirty-five keywords and four soft keywords. These keywords are always available in Python, which means you don’t need to import them. Understanding how to use them correctly is fundamental for building Python programs.
By the end of this tutorial, you’ll understand that:
- There are 35 keywords and four soft keywords in Python.
- You can get a list of all keywords using
keyword.kwlistfrom thekeywordmodule. - Soft keywords in Python act as keywords only in specific contexts.
printandexecare keywords that have been deprecated and turned into functions in Python 3.
In this article, you’ll find a basic introduction to all Python keywords and soft keywords along with other resources that will be helpful for learning more about each keyword.
Get Your Cheat Sheet: Click here to download your free cheat sheet that summarizes the main keywords in Python.
Take the Quiz: Test your knowledge with our interactive “Python Keywords: An Introduction” quiz. You’ll receive a score upon completion to help you track your learning progress:
Interactive Quiz
Python Keywords: An IntroductionIn this quiz, you'll test your understanding of Python keywords and soft keywords. These reserved words have specific functions and restrictions in Python, and understanding how to use them correctly is fundamental for building Python programs.
Python Keywords
Python keywords are special reserved words that have specific meanings and purposes and can’t be used for anything but those specific purposes. These keywords are always available—you’ll never have to import them into your code.
Python keywords are different from Python’s built-in functions and types. The built-in functions and types are also always available, but they aren’t as restrictive as the keywords in their usage.
An example of something you can’t do with Python keywords is assign something to them. If you try, then you’ll get a SyntaxError. You won’t get a SyntaxError if you try to assign something to a built-in function or type, but it still isn’t a good idea. For a more in-depth explanation of ways keywords can be misused, check out Invalid Syntax in Python: Common Reasons for SyntaxError.
There are thirty-five keywords in Python. Here’s a list of them, each linked to its relevant section in this tutorial:
False |
await |
else |
import |
pass |
None |
break |
except |
in |
raise |
True |
class |
finally |
is |
return |
and |
continue |
for |
lambda |
try |
as |
def |
from |
nonlocal |
while |
assert |
del |
global |
not |
with |
async |
elif |
if |
or |
yield |
Two keywords have additional uses beyond their initial use cases. The else keyword is also used with loops and with try and except in addition to in conditional statements. The as keyword is most commonly used in import statements, but also used with the with keyword.
The list of Python keywords and soft keywords has changed over time. For example, the await and async keywords weren’t added until Python 3.7. Also, both print and exec were keywords in Python 2.7 but were turned into built-in functions in Python 3 and no longer appear in the keywords list.
Python Soft Keywords
As mentioned above, you’ll get an error if you try to assign something to a Python keyword. Soft keywords, on the other hand, aren’t that strict. They syntactically act as keywords only in certain conditions.
This new capability was made possible thanks to the introduction of the PEG parser in Python 3.9, which changed how the interpreter reads the source code.
Leveraging the PEG parser allowed for the introduction of structural pattern matching in Python. In order to use intuitive syntax, the authors picked match, case, and _ for the pattern matching statements. Notably, match and case are widely used for this purpose in many other programming languages.
To prevent conflicts with existing Python code that already used match, case, and _ as variable or function names, Python developers decided to introduce the concept of soft keywords.
Currently, there are four soft keywords in Python:
You can use the links above to jump to the soft keywords you’d like to read about, or you can continue reading for a guided tour.
Value Keywords: True, False, None
There are three Python keywords that are used as values. These values are singleton values that can be used over and over again and always reference the exact same object. You’ll most likely see and use these values a lot.
There are a few terms used in the sections below that may be new to you. They’re defined here, and you should be aware of their meaning before proceeding:
Read the full article at https://realpython.com/python-keywords/ »
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February 12, 2025 at 07:30PM
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