Python intern for non-strings

by

The purpose of interning things is to be able to compare them by comparing their memory address; you ensure that you never create two objects with the same value (when the program requests the creation of a second object with the same value as an existing object, it instead receives a reference to the pre-existing object). This requires that the things you’re interning be immutable; if the value of an interned object could change, comparing them by address isn’t going to work.

In Python, it’s not possible to enforce the immutability of user-defined class instances, so it wouldn’t be safe to intern them. I suspect that’s the main theoretical reason intern doesn’t cover class instances.

Other built in immutable types are either comparable in a single machine-level operation already (int, float, etc), or immutable containers that can contain mutable values (tuple, frozenset). There’s no need to intern the former, and the latter can’t be safely interned either.

More Related Contents:

  1. What is the python “with” statement designed for?
  2. Why doesn’t a python dict.update() return the object?
  3. What is the purpose of python’s inner classes?
  4. What is a maximum number of arguments in a Python function?
  5. Python ? (conditional/ternary) operator for assignments [duplicate]
  6. Python intern for non-strings
  7. unindent does not match any outer indentation level python3.6.4 [duplicate]
  8. Importing Tweets via Python using Tweepy
  9. Python – get unique and sorted values in list of lists [closed]
  10. What is the meaning of single and double underscore before an object name?
  11. Extracting an attribute value with beautifulsoup
  12. pygame.event.get() not returning any events when inside a thread
  13. Merge lists that share common elements
  14. pythonw.exe or python.exe?
  15. How do I mock an open used in a with statement (using the Mock framework in Python)?
  16. python multiprocessing on windows, if __name__ == “__main__”
  17. pyplot common axes labels for subplots
  18. python class attribute
  19. How to check if a column exists in Pandas
  20. Regex for existence of some words whose order doesn’t matter
  21. Seaborn showing scientific notation in heatmap for 3-digit numbers
  22. Removing minimize/maximize buttons in Tkinter
  23. How do I add tab completion to the Python shell?
  24. Django required field in model form
  25. What is the common header format of Python files?
  26. How to smooth matplotlib contour plot?
  27. How do I use basic HTTP authentication with the python Requests library?
  28. Python and how to get text from a Selenium element WebElement object
  29. counting combinations and permutations efficiently
  30. ImportError: cannot import name ‘builder’ from ‘google.protobuf.internal’

Leave a Comment