Is it possible to create python list that content is tuple using VarPythonCreate? about python4delphi HOT 4 CLOSED

You can use the following to create lists or tuples

function VarPythonCreate( const AValues : array of const; ASequenceType : TSequenceType = stList ) : Variant; overload;

You could also use

function VarPythonEval( const APythonExpression : AnsiString) : Variant;

e.g VarPythonEval('[("name","=","Kelvin"),("title","=","MR")]')

from python4delphi.

Thanks for your help but this is what i tried, but could not get it work,

1. drop a component TPythonDelphiVar and named it to list1 ,
2. in my delphi code , put as suggested ,
   list1.value := VarPythonEval('[("name","=","Kelvin"),("title","=","MR")]');
3. in my python script , i did the following,
   print 'list1' , 'list1.value' , type(list1.value)
4. it printed output as
   list1 None <type 'NoneType'>

so it is not working for VarPythonEval

then when i tried and see if the TPythonDelphiVar whether it is
working with a simple string ,

1. i change delphi code to
   list1.value :='test';
2. when i check the printed output after execution of my python script is
   L1 test <type 'unicode'>
3. so the python script and delphi code is working .

when i tried again using VarPythonCreate

1. i change delphi code to
   declared local variable ,
   v : array of tvarrec;
   then

   ` SetLength(v,2);
   Format('test1',v);
   Format('test2',v);

   list1.value :=VarPythonCreate( v ,stList);`

2. when i check the printed output after execution of my python script is
   L1 None

3. so the python script and delphi code is NOT working .

is there anything i may have missed ? or the P4D has some bugs for creating list / tuple ?

from python4delphi.

Your original question did not mention TPythonDelphiVar and the like.

TPythonDelphiVar allows you to export simple Delphi values to Python.
VarPyth on the other hand is about manipulating Python objects in Delphi. (high-level)
WrapDelphi is about wrapping Delphi objects and exposing to Python.
Look at the numerous demos and study the code.

Assigning a custom variant to a TPythonDelphiVar.Value is not supported:
list1.value := VarPythonEval('[("name","=","Kelvin"),("title","=","MR")]');
Only simple variant types will work.

On the other hand you may try:
list1.ValueObject := ExtractPythonObjectFrom(VarPythonEval('[("name","=","Kelvin"),("title","=","MR")]'));
might work.

Instead of using a TPythonDelphiVar you can just add a TPythonModule and use the SetVar method.

Finally please do not use the issue tracker to ask for support. Use Stackoverflow, Delphi forums etc.

from python4delphi.

VarPythonEval('[("name","=","Kelvin"),("title","=","MR")]')
or just
GetPythonEngine.EvalString('[("name","=","Kelvin"),("title","=","MR")]')

creates a list of tuples. This is python, nothing to do with P4D.

You can use
function VarPythonCreate( const AValues : array of const; ASequenceType : TSequenceType = stList ) : Variant; overload;
to create either a list or a tuple depending on the second parameter.

from python4delphi.