Wrap TDictionary - TypeError: 'Object' object is not subscriptable

[iqrf 3]

HI,

I modified the example of Demo 32. Added TColumn and fColumn: TDictionary<String,TColumn>;  property ColumnA: TDictionary<String,TColumn> read fColumn write fColumn;

  {$METHODINFO ON}
  TColumn = class(TPersistent)
  private
    FVisible: Boolean;
    FWidth: Integer;
  public
    property Visible: Boolean read FVisible write FVisible;
    property Width: Integer read FWidth write FWidth;
  end;

  TPoint = class(TPersistent)
    private
      fx, fy : Integer;
      fName : String;
      fColumn: TDictionary<String,TColumn>;
    public
      procedure OffsetBy( dx, dy : integer );
    published
      property x : integer read fx write fx;
      property y : integer read fy write fy;
      property Name : string read fName write fName;
      property ColumnA: TDictionary<String,TColumn> read fColumn write fColumn;
  end;
  {$METHODINFO OFF}

procedure TForm1.Button1Click(Sender: TObject);
var
  DelphiPoint : TPoint;
  p : PPyObject;
begin
  // Here's how you can create/read Python vars from Delphi with
  // Delphi/Python objects.
  DelphiPoint := TPoint.Create;
  DelphiPoint.x := 10;
  DelphiPoint.y := 20;

  DelphiPoint.ColumnA := TDictionary<String,TColumn>.Create;
  var value := TColumn.Create;
  value.Visible := True;
  value.Width := 455;
  DelphiPoint.ColumnA.Add('Note', value);
    
  // DelphiPoint will be owned and eventually destroyed by Python
  p := PyDelphiWrapper.Wrap(DelphiPoint, soOwned);

  PythonModule1.SetVar( 'myPoint', p );

  // Note, that you must not free the delphi point yourself.
  // Instead use the GetPythonEngine.Py_XDECREF(obj) method,
  // because the object may be used by another Python object.
  PythonEngine1.Py_DecRef(p);

  // Excecute the script
  PythonEngine1.ExecStrings( memo1.Lines );

end;

if i coll

print(spam.myPoint.ColumnA.Count)
print(spam.myPoint.ColumnA.ContainsKey("Note"))

OK 
1
True

print(spam.myPoint.ColumnA["Note"])  #TypeError: 'Object' object is not subscriptable

for key in spam.myPoint.ColumnA:	#TypeError: 'Object' object is not iterable
    print(key)

How to solve this please.
How to make this work

a = spam.myPoint.ColumnA.Column()
a.Visible = True
a.Width = 111
spam.myPoint.ColumnA.Add("Note1", a)

Thanks

[pyscripter 689]

You need to register the TDictionary<String,TColumn> in Form.Create,

 

PyDelphiWrapper.RegisterDelphiWrapper(TPyClassWrapper<TDictionary<String,TColumn>>).Initialize;

 

Have not tested,  Does it work?

[iqrf 3]

It doesn't work, the class TPyClassWrapper  is not defined anywhere

[pyscripter 689]

Please use the latest version from https://github.com/pyscripter/python4delphi/.  Not the Getit version.

 

Here  

PyDelphiWrapper.RegisterDelphiWrapper(TPyClassWrapper<TDictionary<string, TColumn>>).Initialize;

 

works.

 

You could also subclass TDictionary<string, TColumn>.

 

type
  TColumnDict = class( TDictionary<string, TColumn>)
  end;

and in Form.Create

PyDelphiWrapper.RegisterDelphiWrapper(TPyClassWrapper<TColumnDict>).Initialize;

 

 

[iqrf 3]

Thank you very, very much.  I struggled with it for two days.
Please, how to make the TColumn class visible so it works

col = spam.myPoint.TColumn()
col.Visible = True
col.Width = 255
spam.myPoint.ColumnA.["Note1"] = col

or 
spam.myPoint.ColumnA.["Note1"] = spam.myPoint.TColumn(True, 255)

or do I have to make TPyColumn = class(TPyDelphiPersistent)? 
Thanks

[pyscripter 689]

Assuming your register the dictionary as shown above the following works.

from spam import myPoint

print(myPoint.ColumnA['Note'].Width)
print(myPoint.ColumnA['Note'].Visible)

 

Edited February 28 by pyscripter

[iqrf 3]

Of course it works. I don't know how to put elements of type TColumn into a dictionary ColumnA in Python. 
This doesn't work

col = spam.myPoint.Column()
col.Visible = True
col.Width = 255
spam.myPoint.ColumnA.["Note1"] = col

or 
spam.myPoint.ColumnA.["Note1"] = spam.myPoint.Column(True, 255)

 

[pyscripter 689]

To be able to create columns you need to also to customize the TColumn wrapper:

 

  TColumnWrapper = class(TPyClassWrapper<TColumn>)
    constructor CreateWith(APythonType: TPythonType; args, kwds: PPyObject); override;
  end;
constructor TColumnWrapper.CreateWith(APythonType: TPythonType; args,
  kwds: PPyObject);
var
  W: integer;
  P: PPyObject;
begin
  Create(APythonType);
  GetPythonEngine.PyArg_ParseTuple(args, 'iO:CreateColumn', @W, @P);
  DelphiObject := TColumn.Create;
  DelphiObject.Width := W;
  DelphiObject.Visible := GetPythonEngine.PyObject_IsTrue(P) = 1;
end;

then register it in Form.Create

 

  PyDelphiWrapper.RegisterDelphiWrapper(TColumnWrapper).Initialize;
  PyDelphiWrapper.RegisterDelphiWrapper(TPyClassWrapper<TDictionary<string, TColumn>>).Initialize;  

Then the following code works:

 

from spam import myPoint, Column

print(myPoint.ColumnA['Note'].Width)
print(myPoint.ColumnA['Note'].Visible)

new_column = Column(100, False)
myPoint.ColumnA.Add('Note1', new_column)

print(myPoint.ColumnA['Note1'].Width)
print(myPoint.ColumnA['Note1'].Visible)

 

Edited February 28 by pyscripter

[iqrf 3]

Many thanks once again.

Question about TPyPoint. From python it is always called CreateWith, you cannot call Create. Why is that? I solved it like this.
To write p = spam.Point() , I changed ii: to |ii
PyArg_ParseTupleAndKeywords(args, kwds, '|ii:CreatePoint',
                 @KeyPointerArray[0], @fx, @fy)

[pyscripter 689]

1 hour ago, iqrf said:

Many thanks once again.

Question about TPyPoint. From python it is always called CreateWith, you cannot call Create. Why is that? I solved it like this.
To write p = spam.Point() , I changed ii: to |ii
PyArg_ParseTupleAndKeywords(args, kwds, '|ii:CreatePoint',
                 @KeyPointerArray[0], @fx, @fy)

You could allow for both Point() and Point(x, y) by modifying CreateWith

if PyArg_ParseTupleAndKeywords(args, kwds, '|ICreatePoint') then
  // no arguements

else if PyArg_ParseTupleAndKeywords(args, kwds, 'ii|:CreatePoint', @fx, @fy) then
// two integer arguements
begin

...

end;

 

Edited February 28 by pyscripter

[iqrf 3]

Is there any way to iterate over TDictionary in Python?

for key in spam.myPoint.ColumnA.Keys:  #TypeError: 'Object' object is not iterable
    print(key)

for key, value in spam.myPoint.ColumnA.Items:    #TypeError: 'IndexedProperty' object is not iterable
    print(key, value)

 

Edited February 29 by iqrf

[pyscripter 689]

9 hours ago, iqrf said:

for key in spam.myPoint.ColumnA.Keys: #TypeError: 'Object' object is not iterable print(key😞

Use

for key in spam.myPoint.ColumnA.Keys.ToArray():
    print(key)

 

It is possible to allow for a more natural iteration, but it would require to hand craft the TDictionary wrapper.    See for instance how it is done in TPyDelphiStrings in WrapDelphiClasses.

Edited February 29 by pyscripter

[iqrf 3]

On 2/28/2024 at 4:27 PM, pyscripter said:

To be able to create columns you need to also to customize the TColumn wrapper:

 

  TColumnWrapper = class(TPyClassWrapper<TColumn>)
    constructor CreateWith(APythonType: TPythonType; args, kwds: PPyObject); override;
  end;
constructor TColumnWrapper.CreateWith(APythonType: TPythonType; args,
  kwds: PPyObject);
var
  W: integer;
  P: PPyObject;
begin
  Create(APythonType);
  GetPythonEngine.PyArg_ParseTuple(args, 'iO:CreateColumn', @W, @P);
  DelphiObject := TColumn.Create;
  DelphiObject.Width := W;
  DelphiObject.Visible := GetPythonEngine.PyObject_IsTrue(P) = 1;
end;

then register it in Form.Create

 

  PyDelphiWrapper.RegisterDelphiWrapper(TColumnWrapper).Initialize;
  PyDelphiWrapper.RegisterDelphiWrapper(TPyClassWrapper<TDictionary<string, TColumn>>).Initialize;  

Then the following code works:

 

from spam import myPoint, Column

print(myPoint.ColumnA['Note'].Width)
print(myPoint.ColumnA['Note'].Visible)

new_column = Column(100, False)
myPoint.ColumnA.Add('Note1', new_column)

print(myPoint.ColumnA['Note1'].Width)
print(myPoint.ColumnA['Note1'].Visible)

 

It is possible to somehow distinguish whether the SetVisible function was called from

new_column.visible = True

or

myPoint.ColumnA['Note1'].Visible = True

procedure TColumn.SetVisible(const Value: Boolean);
begin
  FVisible := Value;
  ...
end;

Thanks for the advice.

[pyscripter 689]

On 3/6/2024 at 6:08 PM, iqrf said:

It is possible to somehow distinguish whether the SetVisible function was called from

TColumn.SetVisible is called, so inside that method Self is the TColumn object on which the method is called.