Re: [Numpy-discussion] ***[Possible UCE]*** user-defined type example

[Matt K. <mat...@ho...>]

> Matt Knox wrote:> > Could someone please point me to/provide me with a ba=
sic example of > > creating a user defined type?> >  > > Here is my complet=
ely naive attempt which obviously doesn't work...> >> > import numpy> >  > =
> class myType(numpy.void):> >     def __init__(self,val):> >         self.=
val =3D val> >  > > testType =3D numpy.dtype(myType)> >> > val1 =3D myType(=
5)> > val2 =3D myType(6)> >  > > foo =3D numpy.array([val1,val2],testType)>=
 >  > >  > > Any help would be greatly appreciated. Thanks,> > =20
> A "true" user-defined data-type can only be done in C.> > However.  You c=
an use the "VOID" data-type to create a type with > multiple fields.   What=
 do you want to do with your user-defined data-type.>> -Travis
Thanks for the reply Travis.
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I have a custom Date class which allows creation of different frequency Dat=
es (annual, monthly, etc..). Two dates of the same frequency can be subtrac=
ted, and integers can be added to a Date, with the obvious results in each =
case.  I store these dates in arrays currently using the "object" dtype.
=20
However, the problem with this is that I can't tell the frequency of the Da=
tes in the array without inspecting invidual elements of the array, or subc=
lassing the array object itself. I'd like to be able to have each frequency=
 of date as a data type  (DateAnnual, DateMonthly, etc...). It just seems l=
ike a cleaner approach to have these dates defined as data types.
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I would be open to the idea of defining this in C, but I don't really have =
any examples to work with for that either.
Many thanks for any advice/suggestions you can provide.
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- Matt
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