How to join assignment logs with outcomes in Python

from datetime import datetime, timedelta

class AssignmentLog:
    def __init__(self):
        self.logs = [
            {"assignment_id": 101, "student_id": "S001", "submitted_at": "2024-03-01 10:30:00"},
            {"assignment_id": 101, "student_id": "S002", "submitted_at": "2024-03-02 14:15:00"},
            {"assignment_id": 102, "student_id": "S001", "submitted_at": "2024-03-05 09:45:00"},
        ]
        self.outcomes = [
            {"assignment_id": 101, "student_id": "S001", "grade": "A"},
            {"assignment_id": 101, "student_id": "S002", "grade": "B"},
            {"assignment_id": 102, "student_id": "S003", "grade": "C"},
        ]

    def join_outcomes_present(self):
        """Left join: all log entries, outcome grade if exists."""
        result = []
        for log in self.logs:
            matched = [o for o in self.outcomes 
                       if o["assignment_id"] == log["assignment_id"] 
                       and o["student_id"] == log["student_id"]]
            row = dict(log)
            row["grade"] = matched[0]["grade"] if matched else None
            result.append(row)
        return result

    def join_outcomes_all(self):
        """Full outer join mock: union of log keys and outcome keys."""
        keys = set((l["assignment_id"], l["student_id"]) for l in self.logs)
        keys |= set((o["assignment_id"], o["student_id"]) for o in self.outcomes)
        result = []
        for aid, sid in sorted(keys):
            log_match = next((l for l in self.logs 
                              if l["assignment_id"] == aid and l["student_id"] == sid), None)
            out_match = next((o for o in self.outcomes 
                              if o["assignment_id"] == aid and o["student_id"] == sid), None)
            result.append({
                "assignment_id": aid,
                "student_id": sid,
                "submitted_at": log_match["submitted_at"] if log_match else None,
                "grade": out_match["grade"] if out_match else None,
            })
        return result

if __name__ == "__main__":
    log = AssignmentLog()
    print("Left Join (log-driven):")
    for row in log.join_outcomes_present():
        print(row)
    print("\nFull Outer Join:")
    for row in log.join_outcomes_all():
        print(row)