Object of custom type as dictionary key

by

You need to add 2 methods, note __hash__ and __eq__:

class MyThing:
    def __init__(self,name,location,length):
        self.name = name
        self.location = location
        self.length = length

    def __hash__(self):
        return hash((self.name, self.location))

    def __eq__(self, other):
        return (self.name, self.location) == (other.name, other.location)

    def __ne__(self, other):
        # Not strictly necessary, but to avoid having both x==y and x!=y
        # True at the same time
        return not(self == other)

The Python dict documentation defines these requirements on key objects, i.e. they must be hashable.

More Related Contents:

  1. Adding a element in dictionary which consist of dictionaries.
  2. How to name a file using a value in a list in a dictionary?
  3. I am trying to modify a dictionary value using the exec function
  4. How to copy a dictionary and only edit the copy
  5. Python list of dictionaries search
  6. Replace values in a pandas series via dictionary efficiently
  7. Why is dictionary ordering non-deterministic?
  8. How to keep track of class instances?
  9. merging several python dictionaries
  10. How to save a dictionary to a file?
  11. How to check if a value exists in a dictionary?
  12. How do I combine two lists into a dictionary in Python? [duplicate]
  13. Converting list of tuples into a dictionary
  14. What is the right way to treat Python argparse.Namespace() as a dictionary?
  15. How to reverse a dictionary that has repeated values
  16. How do I serialize a Python dictionary into a string, and then back to a dictionary?
  17. How to create a dictionary of two pandas DataFrame columns
  18. Elegant way to remove fields from nested dictionaries
  19. python: read json and loop dictionary
  20. Python: use mysqldb to import a MySQL table as a dictionary?
  21. Is there a difference between using a dict literal and a dict constructor?
  22. Is self.__dict__.update(**kwargs) good or poor style?
  23. How can I avoid “RuntimeError: dictionary changed size during iteration” error?
  24. Creating a dictionary with list of lists in Python
  25. dataframe to dict such that one column is the key and the other is the value [duplicate]
  26. Python dictionary comprehension using locals() gives KeyError
  27. Mapping dictionary value to list
  28. How to change all the dictionary keys in a for loop with d.items()?
  29. Slicing a dictionary
  30. Random Python dictionary key, weighted by values

Leave a Comment