Python objects compared to .NET objects

Question

I\'m very comfortable with .NET objects and its framework for reference vs value types. How do python objects compare to .NET objects? Specifically, I\'m wondering about equalit

Answer 1

Equality

: - An object with no __cmp__ or __eq__ method defined will raise an error if you try to compare it inherits its comparisons from the object object. This means that doing a > b is equivalent to doing id(a) > id(b).

The is keyword is also used to see if two variables point to the same object. The == operator on the other hand, calls the __cmp__ or __eq__ method of the object it is comparing.

Hashability

: - An object is hashable if there is a __hash__ method defined for it. All of the basic data types (including strings and tuples) have hash functions defined for them. If there is no __hash__ method defined for a class, that class will inherit it's hash from the object object.

Copying

: - copy, copy.deepcopy, and their respective in class methods __copy__ and __deepcopy__. Use copy to copy a single object, deepcopy to copy a heirarchy of objects. deepcopy

Edits made at the suggestion of agf.

Answer 2

In python you can define the __eq__ method to handle the == operator.

The is operator checks if one object is the same as the other. (or more specifically two variables that reference one or two objects)

>>> a = [1, 2, 3]
>>> b = [1, 2, 3]
>>> a == b
True
>>> a is b
False
>>> c = a
>>> c is a
True

Now, this example uses the list type, which you can think of as a class which defines an __eq__ method that compares equality of all its items.

Same for hash, you define a __hash__ method in your class that returns an integer that would identify your object. This is also available in the basic types that support hashing. See the hash function.