How to split two times using frequency in dart? - datetime

Question

So, I need partition two times in dart(startTime and endTime) using an int value called frequency
Start time and End Time are DateTimes respectively. As for an example:
start time: 2021-07-20 10:00:00.000 // 10:00 AM
end time: 2021-07-20 16:00:00.000 // 04:00 PM
frequency: 30
so I need a list which will give my something like:
2021-07-20 10:30:00.000
2021-07-20 11:00:00.000
2021-07-20 11:30:00.000
2021-07-20 12:00:00.000
2021-07-20 12:30:00.000
.......
I have no idea what to do next. But I have created a method called returnTimeDifference which goes something like this:
Duration returnDuration (DateTime? startTime , DateTime? endTime) {
print(
"start time: $startTime \nend Time: $endTime",
);
Duration hourSpan;
workHourSpan = endTime!.difference(startTime !);
print(hourSpan);
return hourSpan;
}
For my above example the method will return 6:00:00.000000. I'm not sure if the value returned from the returnDuration can be used in any matter but I need help splitting the values of two date times into parts using the provided frequency.
N.B: Will it be easier to calculate the values if frequency was in actual Duration?

Answer 1

Repeatedly add your time interval to your start time in a loop until you reach the end time and collect the results. Using a Duration instead of an int for your time interval will be easier and will avoid ambiguity (in your example code, it's unclear if frequency represents a time in minutes, seconds, or if it's supposed to be the number if items you want in the resulting list).
Assuming that your start time and end time are meant to be exclusive endpoints, you could do:
/// Returns a list of [DateTime]s between (but not including) [start] and
/// [end], spaced by [period] intervals.
List<DateTime> getDateTimesBetween({
required DateTime start,
required DateTime end,
required Duration period,
}) {
var dateTimes = <DateTime>[];
var current = start.add(period);
while (current.isBefore(end)) {
dateTimes.add(current);
current = current.add(period);
}
return dateTimes;
}
void main() {
print(getDateTimesBetween(
start: DateTime(2021, 07, 20, 10),
end: DateTime(2021, 07, 20, 16),
period: Duration(minutes: 30),
));
}