Weekday of first day of month

Question

I need to get the weekday of the first day of the month. For example, for the current month September 2013 the first day falls on Sunday.

Answer 1

At first, get the first day of current month (for example):

NSDate *today = [NSDate date];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [gregorian components:(NSEraCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit) fromDate:today];
components.day = 1;
NSDate *firstDayOfMonth = [gregorian dateFromComponents:components];

Then use NSDateFormatter to print it as a weekday:

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];  
[dateFormatter setDateFormat:@"EEEE"]; 
NSLog(@"%@", [dateFormatter stringFromDate:firstDayOfMonth]);

P.S. also take a look at Date Format Patterns

Answer 2

Here is the solution to getting the weekday name of the first day in the current month

NSDateComponents *weekdayComps = [[NSDateComponents alloc] init];
weekdayComps = [calendar.currentCalendar components:calendar.unitFlags fromDate:calendar.today];
weekdayComps.day = 1;
NSDateFormatter *weekDayFormatter = [[NSDateFormatter alloc]init];
[weekDayFormatter setDateFormat:@"EEEE"];
NSString *firstweekday = [weekDayFormatter stringFromDate:[calendar.currentCalendar dateFromComponents:weekdayComps]];
NSLog(@"FIRST WEEKDAY: %@", firstweekday);

For the weekday index, use this

NSDate *weekDate = [calendar.currentCalendar dateFromComponents:weekdayComps];
NSDateComponents *components = [calendar.currentCalendar components: NSWeekdayCalendarUnit fromDate: weekDate];
NSUInteger weekdayIndex = [components weekday];
NSLog(@"WEEKDAY INDEX %i", weekdayIndex);

You can also increment or decrement the month if needed.