how to use NSDateFormatter for different format?

 Hi,
Using the below category for NSDate, you can use below functions to get various date format string or date.

 #import <Foundation/Foundation.h>

@interface NSDate(TCUtils)
- (NSDate *)TC_dateByAddingCalendarUnits:(NSCalendarUnit)calendarUnit amount:(NSInteger)amount;
- (NSString*)TC_dateindisplayformat:(NSString*) format;
- (NSString*)TC_datewithTformat:(NSString*)dt format:(NSString*) format;
- (NSString*)TC_dateformat:(NSString*)dt format:(NSString*) format;
- (NSDate*)TC_stringformat:(NSString*)dt format:(NSString*) format;
- (NSString*)TC_date24format:(NSString*)dt format:(NSString*) format;
- (NSDate*)TC_datewithTformat:(NSString*)dt;
- (BOOL)isSameDay:(NSDate*)anotherDate;
- (NSDate *) todayDateWithoutTime;
@end



#import "NSDate+TCUtils.h"

@implementation NSDate (TCUtils)

- (NSDate *)TC_dateByAddingCalendarUnits:(NSCalendarUnit)calendarUnit amount:(NSInteger)amount {
    NSDateComponents *components = [[NSDateComponents alloc] init];
    NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    NSDate *newDate;
   
    switch (calendarUnit) {
        case NSSecondCalendarUnit:
            [components setSecond:amount];
            break;
        case NSMinuteCalendarUnit:
            [components setMinute:amount];
            break;
        case NSHourCalendarUnit:
            [components setHour:amount];
            break;
        case NSDayCalendarUnit:
            [components setDay:amount];
            break;
        case NSWeekCalendarUnit:
            [components setWeek:amount];
            break;
        case NSMonthCalendarUnit:
            [components setMonth:amount];
            break;
        case NSYearCalendarUnit:
            [components setYear:amount];
            break;
        default:
            ////NSLog(@"addCalendar does not support that calendarUnit!");
            break;
    }
   
    newDate = [gregorian dateByAddingComponents:components toDate:self options:0];
    [components release];
    [gregorian release];
    return newDate;
}

- (NSString*)TC_dateindisplayformat:(NSString*) format
{
    NSDateFormatter* df=[[[NSDateFormatter alloc] init] autorelease];
    [df setTimeZone:[NSTimeZone defaultTimeZone]];
    NSLocale *locale = [[[NSLocale alloc]
                         initWithLocaleIdentifier:@"en_US_POSIX"] autorelease]; 
    [df setLocale:locale];
    [df setDateFormat:format];
    return [df stringFromDate:self];   
}

- (NSString*)TC_datewithTformat:(NSString*)dt format:(NSString*) format
{
    NSDateFormatter* df=[[[NSDateFormatter alloc] init] autorelease];
    [df setTimeZone:[NSTimeZone defaultTimeZone]];
    NSLocale *locale = [[[NSLocale alloc]
                         initWithLocaleIdentifier:@"en_US_POSIX"] autorelease]; 
    [df setLocale:locale];
    [df setDateFormat:@"yyyy-MM-dd"];
    NSArray* a=[dt componentsSeparatedByString:@"T"];
    NSDate* tdt;
    if([a count]>0){
        tdt=[df dateFromString:[a objectAtIndex:0]];
    }
    else{
        tdt=[NSDate date];
    }
    [df setDateFormat:format];
   
    return [df stringFromDate:tdt];
}

- (NSString*)TC_dateformat:(NSString*)dt format:(NSString*) format
{
    NSDateFormatter* df=[[[NSDateFormatter alloc] init] autorelease];
    [df setTimeZone:[NSTimeZone defaultTimeZone]];
    NSLocale *locale = [[[NSLocale alloc]
                         initWithLocaleIdentifier:@"en_US_POSIX"] autorelease]; 
    [df setLocale:locale];
    [df setDateFormat:@"yyyy-MM-dd"];
    NSDate* tdt=[df dateFromString:dt];
    [df setDateFormat:format];
   
    return [df stringFromDate:tdt];
}

- (NSDate*)TC_stringformat:(NSString*)dt format:(NSString*) format
{
    NSDateFormatter* df=[[[NSDateFormatter alloc] init] autorelease];
    [df setTimeZone:[NSTimeZone defaultTimeZone]];
    NSLocale *locale = [[[NSLocale alloc]
                         initWithLocaleIdentifier:@"en_US_POSIX"] autorelease]; 
    [df setLocale:locale];
    [df setDateFormat:format];

    return [df dateFromString:dt];
}

- (NSDate*)TC_datewithTformat:(NSString*)dt
{
    NSDateFormatter* df=[[[NSDateFormatter alloc] init] autorelease];
    [df setTimeZone:[NSTimeZone defaultTimeZone]];
    NSLocale *locale = [[[NSLocale alloc]
                         initWithLocaleIdentifier:@"en_US_POSIX"] autorelease];
    [df setLocale:locale];
    dt=[dt stringByReplacingOccurrencesOfString:@"T" withString:@" "];
    [df setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
    return [df dateFromString:dt];
}

- (NSString*)TC_date24format:(NSString*)dt format:(NSString*) format
{
    NSDateFormatter* df=[[[NSDateFormatter alloc] init] autorelease];
    [df setTimeZone:[NSTimeZone defaultTimeZone]];
    NSLocale *locale = [[[NSLocale alloc]
                         initWithLocaleIdentifier:@"en_US_POSIX"] autorelease]; 
    [df setLocale:locale];
    [df setDateFormat:@"yyyy-MM-dd hh:mm a"];
    NSDate* tdt=[df dateFromString:dt];
    [df setDateFormat:format];
   
    return [df stringFromDate:tdt];
}

- (NSDate *) todayDateWithoutTime
{
    NSDateFormatter *df = [[[NSDateFormatter alloc] init] autorelease];
      [df setTimeZone:[NSTimeZone  defaultTimeZone]];
    NSLocale *locale = [[[NSLocale alloc]
                         initWithLocaleIdentifier:@"en_US_POSIX"] autorelease];
    [df setLocale:locale];
    [df setDateFormat:@"yyyy-MM-dd"];

    NSString *todayDateS = [df stringFromDate:[NSDate date]];
    NSDate *todayDate = [df dateFromString:todayDateS];
    return todayDate;
}



- (BOOL)isSameDay:(NSDate*)anotherDate{
    NSCalendar* calendar = [NSCalendar currentCalendar];
    NSDateComponents* components1 = [calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit) fromDate:self];
    NSDateComponents* components2 = [calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit) fromDate:anotherDate];
    return ([components1 year] == [components2 year] && [components1 month] == [components2 month] && [components1 day] == [components2 day]);
}

@end