Question

I’m probably going about this all wrong but…

I am trying to populate a QTreeView from SQL data – using QAbstractItemModel (and having a great deal of trouble understanding it tbh). One of the tutorials I am following (the simplest) populates the Tree by simply calling new instances of the ‘Node’ and generating the model from the list. The Node has a name and a parentnode (as below). This is OK where you are generating the data within the program. This I can just about follow 🙂

However, I want to bring the data in from the table and use a string to identify the correct parentnode – mainly because if I am iterating over the records I won’t be able to name each one using a separate variable(?). It will be for x in recs: node = Node(“name”, parentnode).

When I do this, I get the obvious error message that the string isnt the correct object and has no methods. Is there a way of using a string derived from my table to identify the correct ‘parent’ object (either that, or could somebody point me in the direction of a very basic Qtreeview model tutorial designed for very enthusiastic, but not necessary gifted learners).

rootNode   = Node("Hips")
childNode0 = TransformNode("RightPirateLeg",        rootNode)
childNode1 = Node("RightPirateLeg_END",    childNode0)
childNode2 = CameraNode("LeftFemur",             rootNode)
childNode3 = Node("LeftTibia",             childNode2)
childNode4 = Node("LeftFoot",              childNode3)
childNode5 = LightNode("LeftFoot_END",          childNode4) 

I realise that I am probably running before I can walk here and apologise in advance for my ignorance.

Answer 1

Are the strings the names of global variables? If so, you can access the value refenced by the global variable with globals()['name'], (replacing 'name' with the string name of the variable of course.)

Or, better yet, instead of littering variable names all over your global namespace
you could use a dict:

node={}
node['rootNode']=Node('Hips')
node['childNode0']=TransformNode('RightPirateLeg',node['rootNode'])
...

This makes it very easy to map between string names and values.