Run a particular Python function in C# with IronPython

Question

So far I have a simple class that wraps a python engine (IronPython) for my use. Although code looks big it's really simple so I copy it here to be more clear with my issue.

Here's the code:

public class PythonInstance
{
    ScriptEngine engine;
    ScriptScope scope;
    ScriptSource source;

    public PythonInstance()
    {
        engine = Python.CreateEngine();
        scope = engine.CreateScope();
    }

    public void LoadCode(string code)
    {
        source = engine.CreateScriptSourceFromString(code, Microsoft.Scripting.SourceCodeKind.Statements);
        source.Compile();
    }

    public void SetVariable(string key, dynamic variable)
    {
        scope.SetVariable(key, variable);
    }

    public void RunCode()
    {
        source.Execute(scope);
    }

    public void CallFunction(string function)
    {
        //?????? no idea what to call here
    }

}

So, it works great but it only allows me to execute all python script at once... but what I would like to do is to be able to call particular functions from within a pythos script.

So, my question: How do I call particular function in the loaded script?

I was trying to find some information or tutorials but unfortunately couldn't find anything.

Avalon

Have you looked at #13232413 and #7053672? – Winther

@Simon first yes, second no. Thank you for the link, I will read it now. – Avalon

Answer 1

Thanks to suggestion in comments I was able to figure out how to use it. Here's what I have now:

public class PythonInstance
{
    private ScriptEngine engine;
    private ScriptScope scope;
    private ScriptSource source;
    private CompiledCode compiled;
    private object pythonClass;

    public PythonInstance(string code, string className = "PyClass")
    {
        //creating engine and stuff
        engine = Python.CreateEngine();
        scope = engine.CreateScope();

        //loading and compiling code
        source = engine.CreateScriptSourceFromString(code, Microsoft.Scripting.SourceCodeKind.Statements);
        compiled = source.Compile();

        //now executing this code (the code should contain a class)
        compiled.Execute(scope);

        //now creating an object that could be used to access the stuff inside a python script
        pythonClass = engine.Operations.Invoke(scope.GetVariable(className));
    }

    public void SetVariable(string variable, dynamic value)
    {
        scope.SetVariable(variable, value);
    }

    public dynamic GetVariable(string variable)
    {
        return scope.GetVariable(variable);
    }

    public void CallMethod(string method, params dynamic[] arguments)
    {
        engine.Operations.InvokeMember(pythonClass, method, arguments);
    }

    public dynamic CallFunction(string method, params dynamic[] arguments)
    {
        return engine.Operations.InvokeMember(pythonClass, method, arguments);
    }

}

To test it:

        PythonInstance py = new PythonInstance(@"
class PyClass:
    def __init__(self):
        pass

    def somemethod(self):
        print 'in some method'

    def isodd(self, n):
        return 1 == n % 2
");
        py.CallMethod("somemethod");
        Console.WriteLine(py.CallFunction("isodd", 6));

Avalon

Answer 2

You can use ScriptScope.GetVariable to get the actual function and then you can call it like a c# function. Use it like this: C# code:

var var1,var2=...
ScriptEngine engine = Python.CreateEngine();
ScriptScope scope = engine.CreateScope();
engine.ExecuteFile(@"C:\test.py", scope);
dynamic testFunction = scope.GetVariable("test_func");
var result = testFunction(var1,var2);

Python code:

def test_func(var1,var2):
    ...do something...

Took me a while to finally figure it out, and it's quite simple.. Too bad there's no good IronPython documentation. Hope this helps :)

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