Iterate through dictionary and store values - ios

Question

I have a dictionary of data which looks like this:
{
asr = "4:23 pm";
dhuhr = "12:02 pm";
fajr = "1:17 am";
isha = "10:47 pm";
maghrib = "8:23 pm";
shurooq = "3:41 am";
}
My goal is to determine which time comes next. My plan is to convert these to actual NSDates using this code:
//create an NSDate with todays date and the right prayer time
NSString *prayerDateString = [curDate stringByAppendingString: #" "];
prayerDateString = [prayerDateString stringByAppendingString: time];
NSLog(#"prayer date string: %#", prayerDateString);
//convert string back to date
NSDate *prayerDateAndTime = [dateAndTimeFormatter dateFromString:prayerDateString];
[dictionaryOfDatesAsDates addObject:prayerDateAndTime];
Which I think works, but I'm not sure if it correctly retains the format of the dictionary. Then to use [currentDate timeIntervalSinceNow] to check each one and assume that the smallest positive time interval will be the next time and to get the name, eg asr.
I'm not sure how to do the iteration and store the time interval value somewhere along with the name of the time in order to get which is the smallest value from this?
How would I go about achieving this?

Answer 1

So, you've got your dates and added them to an array:
NSArray *prayerDateAndTimes = ...
Following on from yesterday:
Get a list of the dates, then use an NSPredicate to filter that list to dates >= [NSDate date], then sort it ascending. Then the first item in the filtered, sorted array will be the next date.
First, filter out dates that have already passed:
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"SELF >= %#", [NSDate date]];
NSArray *validPrayerDateAndTimes = [prayerDateAndTimes filteredArrayUsingPredicate:predicate];
Now we can tell if there are any more dates today:
if (validPrayerDateAndTimes.count > 0) {
// yay, sort to find the next one
validPrayerDateAndTimes = [validPrayerDateAndTimes sortedArrayUsingSelector:#selector(compare:)];
NSLog(#"next date: %#", [validPrayerDateAndTimes objectAtIndex:0]);
} else {
NSLog(#":-(");
}

Answer 2

EDITED:
This should work. Change your dictionary to 24hour format (20:23). It will return the key that has the closest time to current time (even if it has no more prays for today, it will return the next day's).
-(NSDate*)initDateWithHour:(int)hour andMinutes:(int)minutes
{
NSCalendar *calendar = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
NSDateComponents *components = [[[NSDateComponents alloc] init] autorelease];
NSDateComponents *nowComp = [[NSCalendar currentCalendar] components:NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit fromDate:[NSDate date]];
[components setYear:[nowComp year]];
[components setMonth:[nowComp month]];
[components setDay:[nowComp day]];
[components setHour:hour];
[components setMinute:minutes];
return [calendar dateFromComponents:components];
}
- (NSString*)getClosestTimeKey:(NSDictionary*)dict
{
NSDate* now = [NSDate date];
int secondsOfDay = 86400;
int minDif = secondsOfDay;
NSString* closestKey = #"";
for (NSString* key in dict)
{
NSString* timeStr = [dict objectForKey:key];
NSArray *array = [timeStr componentsSeparatedByString:#":"];
int hour = [[array objectAtIndex:0] intValue];
int minutes = [[array objectAtIndex:1] intValue];
NSDate *d = [self initDateWithHour:hour andMinutes:minutes];
int dif = [d timeIntervalSince1970] - [now timeIntervalSince1970];
if (dif < 0)
dif += secondsOfDay;
if (dif < minDif)
{
minDif = dif;
closestKey = key;
}
}
return closestKey;
}
And you use it by:
NSString* key = [self getClosestTimeKey:dict];