Help adding a loop inside a loop

[deanhystad]

You have two loops that read events from the database. One to get the reminder message and one to get the reminder time. You should GET the reminders message and scheduled times at the same time, just like I did in my example. One loop, not two.

Using two loops is messing you up. First you get all your times, then you schedule your reminders. Because of this you schedule all your events to use the same time. The last time retrieved from the database.

Why are you doing this?

    #Convert scheduled_time from Tuple to List
    from itertools import chain
    DateTimeList = list(chain.from_iterable(scheduled_time))
    #Then Convert the List to a String
    DateTimeStr = "".join(str(x) for x in DateTimeList)

Do you understand any of that code? This is the most convoluted scheme I've ever seen to get a value from a tuple.

I don't understand your confusion about tuples. A tuple is just like a list, except it is immutable. If you want to get the value from the tuple, use indexing (scheduled_time[0]) or unpacking (*scheduled_time), just like you would do to get values from a list. When you fix your program to retrieve the reminder message and scheduled time together with a single query, unpacking will be the best choice.

    for message, sched_time in db.execute("SELECT Reminder, DateTime FROM Reminders"):
        schedule_reminder(message, sched_time)

I no longer think Datetime is the right type for saving schedule time in the database. You need timestamps for scheduling and sqlite allows saving timestamps in their native format, unlike DateTime that must be converted to/from a string. Using timestamps for the schedule time also makes it possible to use queries to delete old reminders, or only retrieve reminders that occur during a specific time span. That would be a nice feature if you want to display a calendar of events. The only disadvantage of timestamps is they are not human readable. To input a schedule time you'll need to convert a string to a timestamp (strptime() to convert string to DateTime, timestamp() to convert DateTime to timestamp(). To display a schedule time you'll need to convert a timestamp to a string (.fromtimestamp() to convert timestamp to DateTime, strftime() to convert DateTime to string).

import sqlite3 as sql
from datetime import datetime
import sched, time
 
time_format = "%I:%M %p"
 
def send_reminder(sched_time, message):
    """Print time> Message and scheduled time"""
    sched_time = datetime.fromtimestamp(sched_time).strftime(time_format)
    now = datetime.now().strftime(time_format)
    print(f"{now}> {message}\nScheduled: {sched_time}\n")

def enter_reminders():
    """Generate a list of reminders.  End by entering a blank message"""
    while True:
        reminder = input("Message: ")
        if not reminder:
            break
        sched_time = datetime.strptime(input("HH:MM AM/PM: "), time_format)
        sched_time = datetime.now().replace(
            hour=sched_time.hour,
            minute=sched_time.minute,
            second=0)
        yield sched_time.timestamp(), reminder


def save_reminders(reminders):
    """Make a table in the database to hold the reminders
    Table reminders
    Time a timestamp, Reminder a string
    """
    db = sql.connect("test.db")
    db.execute("CREATE TABLE IF NOT EXISTS reminders(Time INTEGER, Reminder TEXT)")
    db.execute("DELETE FROM reminders")  # For demonstration purposes only
    for reminder in reminders:
        db.execute(
            "INSERT INTO reminders (Time, Reminder) VALUES(?, ?)", reminder)
    db.commit()
    db.close()
 
def schedule_reminders(schedule):
    """Get reminders from the database and add to the schedule."""
    db = sql.connect("test.db")
    for sched_time, reminder in db.execute("SELECT Time, Reminder FROM reminders"):
        schedule.enterabs(sched_time, 1, send_reminder, (sched_time, reminder))
    db.close()

print("Enter reminders")
save_reminders(enter_reminders())

print("\nScheduling reminders:")
schedule = sched.scheduler(time.time)
schedule_reminders(schedule)

print("\nPlay reminders.")
while not schedule.empty():
    schedule.run()