How to a, b = myClass(a, b) in Python?

Question

Python does this:

t = (1, 2)
x, y = t
# x = 1
# y = 2

How can I implement my class so to do

class myClass():
    def __init__(self, a, b):
        self.a = a
        self.b = b

mc = myClass(1, 2)
x, y = mc
# x = 1
# y = 2

Is there a magic function I could implement in order to achieve this?

`tuple(1, 2)` is not a valid `tuple` call. – user2357112 Mar 11 '20 at 21:48 — user2357112, Mar 11 '20 at 21:48
@user2357112 I fixed it, along with the `__init__` method – wjandrea Mar 11 '20 at 22:09 — wjandrea, Mar 11 '20 at 22:09

score 3 · Accepted Answer · edited Mar 11 '20 at 22:07

3

You need to make your class iterable. Do this by adding the __iter__ method to it.

class myClass():
    def __init__(self, a, b):
        self.a = a
        self.b = b

    def __iter__(self):
        return iter([self.a, self.b])

mc = myClass(1, 2)

x, y = mc

print(x, y)

Output:

1 2

edited Mar 11 '20 at 22:07

wjandrea

28,235
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answered Mar 11 '20 at 21:02

rdas

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What about a meta-scope where I can do this ? myClass_atrributename = myClass(a, b). So if your class has an attribute named “myClass_attributename” to return that value – Mar 11 '20 at 21:05
2

I'm not sure if I understood that – rdas Mar 11 '20 at 21:06
1

I think @entropyfeverone might be trying to refer to `getattr`? Like `getattr(myclass(a, b), 'myClass_attributename')` – Tomerikoo Mar 11 '20 at 21:45

score 1 · Answer 2 · answered Mar 11 '20 at 22:17

If your class doesn't do much else, you might prefer to use a named tuple:

from collections import namedtuple

MyClass = namedtuple('MyClass', 'a b')
mc = MyClass(1, 2)
print(mc.a, mc.b)  # -> 1 2
x, y = mc
print(x, y)  # -> 1 2

BTW, style note: Class names should be UpperCamelCase.

How to a, b = myClass(a, b) in Python?

2 Answers2