ml-models | Machine Learning Procedures and Functions for Neo4j | Graph Database library

Only some types of variables are exportable to QML, among them are str, int, float, list but in the case of a dictionary it must be exported as a QVariant.

On the other hand if you want to access a method from QML then you must use the @pyqtSlot or @Slot decorator if you are using PyQt5 or PySide2, respectively, indicating the type of input data that in this case is int and the type of output through of the result parameter.

main.py

It is in sklearn.linear_model, https://scikit-learn.org/stable/modules/generated/sklearn.linear_model.LogisticRegression.html

You did that wrong. Array members must be ListElement:

Try this, it'll do your job:

The issue was that fields (defined above) is a java.util.List which needs to be converted into Scala List. The solution was the following:

Import JavaConverters

I have come to the conclusion that exporting a spark R model is not supported. I have added a feature request for this: https://issues.apache.org/jira/browse/SPARK-21430. Please vote on the jira ticket if you are also looking for this functionality.

The one prominent downside of the usage of QObject as a model item is because the base class is pretty big, it is kind of a "god object" (which is an anti-pattern) that contains a whole lot of stuff you don't really need most of the time. As a result, it has about 160 bytes of "overhead" on top of any model data that you may have. Which may be problematic if you have a big model with lots of items, and the items themselves are relatively small. You end up with a lot of overhead.

A QObjectList as a model is always a bad idea, unless you are doing something entirely trivial. Since it doesn't implement the proper interface to notify referencing views of changes, the only way is to force an update, which will redraw the entire model each time rather than just the changes.

There is no requirement on what item objects are, as long as you implement the model properly.

The second implementation in particularly useful for a number of reasons:

• you don't need to bother with implementing a specific "static" model with fixed roles for each and every usage scenario
• your model items can have fundamentally different properties, you are not limited to a model "schema"
• you automatically get notifications for bindings in QML since you are dealing with QObject and Q_PROPERTY
• you can define models in declarative, and you can even nest models to create tree structures, which you cannot do with ListModel.
• you can define the actual model items in pure QML without having to recompile all the time, a.k.a rapid prototyping, and when done, you can simply port the objects to C++
• at the same time, on top of all the advantages, the model is actually much simpler to implement and maintain than a regular "rigid" model, the role lookup is faster, since you essentially have a single object role and no lookup whatsoever, there is no need to implement data change signals for roles and so on... easy peasy

Though I agree with Kevin Krammer and xander, you have multiple ways to surpress bindings.

Either you can bind them with the signal.connect(slotToConnect) and disconnect them with signal.disconnect(slotToDisconnect) directly, or you use Connections with a enabled-value that you change uppon start and completion of the sorting.

Further you should consider to display some BusyIndicator when you have some actions taking longer than a few ms.

But I need to admit, I can't see no reason for doing this in JS

You will have to iterate and check the list elements.

It is a good idea to write a function if you are going to be performing different searches, where you can pass search criteria as a functor: