How to handle data in python similar to IDL structures?

Question

So I am converting some code from IDL to python. In the IDL there are about 50 variables held in a structure of structures;

values = { struct1: {a = 1, b = 2}, struct2: {a = 3, b = 4} ... etc }

The data can be accessed as follows:

print, values.struct1.a
# 1

Is there an easy way to do this in python where I can still have methods in the class values that act on the inner classes? For instance, having one setValues method that can change values in struct1 or struct2? I was hoping for something like this:

class values:
    def __init__(self):
         self.struct1 = self.struct1()
         self.struct2 = self.struct2()

    class struct1:
         def __init__(self):
             self.a = 1
             self.b = 2
    class struct2: 
         def __init__(self):
             self.c = 3
             self.d = 4

    def setValues(self, **kwargs):
        for key,value in kwargs.items():
             setattr(self, key, value)
        return

Where I could execute the following code:

st = values()
st.setValue(struct1.a = 2.0, struct2.a = 5.0)
print, st.struct1.a , st.struct2.a
# 2.0
# 5.0

but I get the following error:

AttributeError: values instance has no attribute 'struct1'

I am pretty new to python and was curious if anyone had some insight on a better way to produce a nested class and have methods that can act on all nests.

Raydel, rather than editing the original question, you should post what you did to fix the issue as an answer. — ElGavilan, Apr 16 '14 at 17:20

Raydel Miranda · Accepted Answer · 2014-04-16T20:36:09.553

Having the code:

class values:

    class struct1:
         def __init__(self):
             self.a = 1
             self.b = 2

    class struct2: 
         def __init__(self):
             self.c = 3
             self.d = 4

    def __init__(self):
         self.struct1 = self.struct1()
         self.struct2 = self.struct2()

    def setValue(self, **kwargs):
        for key, value in kwargs.items():
            try:
                getattr(self.struct1, key)
            except AttributeError:
                # self.struct1 don't have any attribute which name is the value of 'key'.
                pass
            else:
                setattr(self.struct1, key, value)

            try:
                getattr(self.struct2, key)
            except AttributeError:
                # self.struct2 don't have any attribute which name is the value of 'key'.
                pass
            else:
                setattr(self.struct2, key, value)

You can:

>>> st = values()
>>> st.struct1.a = 10
>>> st.struct2.c = 20
>>> print(st.struct1.a)
>>> 10
>>> print(st.struct2.c)
>>> 20
>>> st.setValue(b=20, a=100, d=50, c=60)
>>> print(st.struct1.a)
>>> print(st.struct1.b)
>>> print(st.struct2.c)
>>> print(st.struct2.d)
>>> 100
>>> 20
>>> 60
>>> 50

EDIT: In your original question you had __init instead __init__ and:

self.struct1 = self.struct1()
self.struct1 = self.struct2()   # Here you was redefining self.struct1

I changed to:

self.struct1 = self.struct1()
self.struct2 = self.struct2()

I still can't use a single setValue method to change data from either nested class. If I try something like st.struct1.setValue(a=2.0) there is an error that struct1 has no instance setValue and if I try st.setValue(struct1.a = 2.0) it responds that the keyword can't be an expression. Is there anyway to get around this without having to have a setValue method in each subclass? — jjohnson28, Apr 16 '14 at 19:48
@jjohnson28 Answer edited. With the new version you can use `setValue` as you want. — Raydel Miranda, Apr 16 '14 at 20:37

How to handle data in python similar to IDL structures?

1 Answers1