Export nbgrader as per-assignment CSV files with per-question columns

vubexport.py

import pathlib

from nbgrader.plugins import ExportPlugin
from nbgrader.api import Gradebook, MissingEntry


class VubExporter(ExportPlugin):
    def export(self, gradebook: Gradebook) -> None:
        if self.to == "":
            dest = "grades"
        else:
            dest = self.to

        pathlib.Path(dest).mkdir(parents=True, exist_ok=True)

        for assignment in gradebook.assignments:
            keys = [
                "student_id",
                "submission_time",
                "needs_manual_grade",
            ]
            
            # assignment.submissions
            if len(assignment.notebooks) == 0:
                continue
            
            cells = []
            for notebook in assignment.notebooks:
                for cell in notebook.grade_cells:
                    cells.append(notebook.name + "/" + cell.id)
                    keys.append("cell " + notebook.name + "/" + cell.id + " (" + str(int(cell.max_score)) + ")")
            
            fh = open(dest + "/" + assignment.name + ".csv", "w")
            fh.write(", ".join(keys) + "\n")
            
            for student in gradebook.students:
                try:
                    submission = gradebook.find_submission(assignment.name, student.id)
                except MissingEntry:
                    continue
                student_grades = ["0"] * len(cells)
                for notebook in submission.notebooks:
                    for grade in notebook.grades:
                        key = notebook.name + "/" + grade.cell_id
                        key = cells.index(key)
                        student_grades[key] = str(grade.score)
                fh.write(", ".join([student.id, submission.timestamp.isoformat(), str(submission.needs_manual_grade)]))
                fh.write(", ")
                fh.write(", ".join(student_grades) + "\n")