Add a method to a list instance in python

Question

I want to add a method to a single instance of the 'list' class. Example:

a = [1,2]
a.first = lambda self: return self[0]

I know this don't work, but I want something like that works like that. I know its not a good practice, and I know I should do a whole new class, but I think this is possible in Python and haven't figured out how.

I am aware of: Dynamically add member function to an instance of a class in Python and Dynamically binding Python methods to an instance correctly binds the method names, but not the method

but none of those work with a native list.

Thanks!

You want to do a.first = lambda: a[0] or a.first = types.MethodType(lambda self: self[0], a). If you add a function to an object like this Python won't automatically bind it to the object. — Peter Graham
– Peter Graham, Commented Sep 22, 2011 at 2:14

Ignacio Vazquez-Abrams · Accepted Answer · 2011-09-21 22:18:30Z

13

Nothing will work with a native list, since you cannot add methods to a type defined in C. You will need to derive from list and add your method to that class.

answered Sep 21, 2011 at 22:18

Ignacio Vazquez-Abrams

804k160 gold badges1.4k silver badges1.4k bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Add a method to a list instance in python

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related