[IronPython] How to reference List objects?

[Justin Regele]

Ah, I see. Would a python list then need to be called the way he is doing
it, though. Is this a silverlight issue? I am wondering if he can just make
a python list out of his Book C# class rather than exporting them as a list.
I am sure there would be some performance issues, so maybe that is the
reason for this way of doing it.

Wondering about this error:
System.Collections.Generic.List'1[testapp.PythonEngine+book]

What does the '+' indicate?


On Mon, Jun 8, 2009 at 1:32 PM, Michael Foord <fuzzyman at voidspace.org.uk>wrote:

> Justin Regele wrote:
>
>> Type Errors where the object is unscriptable means that it does not have
>> any indices intialized.
>>
>> Use the python interactive interpreter to play around with list methods,
>> and see how they work correctly. This is one of pythons best weapons. if you
>> don't know what objects are in a module, or what attributes/methods are in a
>> class type in dir(<module or classname>) and it will spell it out for you.
>>
>> you do need to initialize a list before access, however.
>> so you CANT do this
>>
>> x = []
>> x[0] = 'something'
>>
>> you would have to do this(making a list of 10 None objects)
>> x = [None] * 10
>> x[0] = 'something'
>>
>> OR use the append() method to make the list more like a dynamic array
>>
>> x = []
>> x.append('something')
>>
>> this is the python way of doing it, but i'm not sure why you need a .NET
>> list array.
>>
>
> He is creating the list from C# and making it available to Python code. As
> far as I can tell he is doing it right, although maybe the fact that his C#
> book class is private is interfering with it?
>
> Michael
>
>
>
>> On Mon, Jun 8, 2009 at 11:27 AM, Larry Danberger <
>> larry.danberger at nubium.com <mailto:larry.danberger at nubium.com>> wrote:
>>
>>    Hi all,
>>    I'm new to Python and IronPython, sorry if this is obvious.  I
>>    haven't found
>>    answer searching web or in IronPython In Action book...
>>
>>    I have embedded IronPython into silverlight app for scripting,
>>    which is
>>    working (wow! Btw).  I use scope.SetVariable for dictionaries
>>    which works as
>>    expected.
>>
>>    However when passing in a list I am unable to access the objects
>>    within a
>>    list.
>>    For the example below when trying
>>    x = books[0].Name
>>    I get
>>    TypeError: 'List[books]' object is unsubscriptable
>>
>>    If I do
>>    x = books
>>    I get back
>>    System.Collections.Generic.List'1[testapp.PythonEngine+book]
>>
>>    If I do
>>    Len(books)
>>    I get back 4.
>>
>>    How do I access them individually (by name etc.)?
>>
>>    My code looks something like this:
>>
>>    Class book
>>    {
>>      int ID { get; set; }
>>      String Name { get; set; }
>>      String Author { get; set; }
>>      String Description { get; set; }
>>    }
>>
>>    ...
>>    List<book> _books = new List<book>();
>>
>>    _books.Add(new book { ID=1, Name="book1", Author="author1",
>>    Description="Description1"});
>>    _books.Add(new book { ID=2, Name="book2", Author="author2",
>>    Description="Description2"});
>>    _books.Add(new book { ID=3, Name="book3", Author="author3",
>>    Description="Description3"});
>>    _books.Add(new book { ID=4, Name="book4", Author="author4",
>>    Description="Description4"});
>>
>>    ...
>>    _scope.SetVariable("books", _books);
>>
>>
>>    Any help appreciated, thanks!
>>    -Larry
>>
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>
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