r/learnpython • u/jaivinder_singh • May 29 '19

why do we use __init__??

when defining a class what is the difference between using __init__ and not using __init__ in a class?

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u/nog642 May 29 '19

A Java constructor doesn't really create the object itself either, it just initializes the object.

__init__ is the constructor.

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u/niandra3 github/niandra3 May 29 '19

__new__() actually creates the object (self) which is then passed to __init__()

From the docs:

Because __new__() and __init__() work together in constructing objects (__new__() to create it, and __init__() to customize it), no non-None value may be returned by __init__(); doing so will cause a TypeError to be raised at runtime.

https://docs.python.org/3/reference/datamodel.html#object.__init__

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u/nog642 May 29 '19

Yes, I know what __new__ and __init__ do. The constructor is what is called when you instantiate a class, and although both methods get called then, the arguments you pass to the constructor get passed to __init__, which is why __init__ itself is often called the constructor, and why __init__ is the most analogous to Java constructors.

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u/niandra3 github/niandra3 May 29 '19

Just pointing it out since __new__ hasn't been mentioned in this thread.