PythonInterpreter in Jython - storing result

Question

I've redirected the console output to a txt file for the code below, however is there a way to assign the result to a local variable instead? e.g. if the output is 'Hello World' I'd like to assign this to a String variable.

I'm looking at the PythonInterpreter API and I am slightly confused as it's new to me (http://www.jython.org/javadoc/org/python/util/PythonInterpreter.html).

I've been playing around with the setIn and setOut methods, but haven't got it working.

Would be very grateful for some advice.

public static void main(String[] args) {

    // Create an instance of the PythonInterpreter
    PythonInterpreter interp = new PythonInterpreter();

    // The exec() method executes strings of code
    interp.exec("import sys");
    interp.exec("print sys");

    interp.execfile("C:/Users/A/workspace/LeaerningPyDev/helloWorld.py");

}

Answer 1

To get the command-line output of the executed Python-script into a Java-String, first create a java.io.ByteArrayOutputStream (https://docs.oracle.com/javase/8/docs/api/java/io/ByteArrayOutputStream.html); let's call it bout. Then call interp.setOut(bout). After calling interp.execfile(...) you should be able to retrieve its output as a Java-String via bout.toString().

However, in general it is more elegant not to do such stuff via the system-out/in. Instead you can use interp.eval(some python expression), which returns the expression's result as a PyObject. On the PyObject you can use Jython-API to turn it into a corresponding Java standard-type or do whatever you want with it. If you want to use a more complex script (rather than a single expression), you can use interp.get(variable name) to retrive certain objects created by your script as PyObjects.