iOS: Compare two less or equal NSDates [duplicate]

问题

I want to compare two dates and do something when one is less or equal than the other, I tried to do it this way:

if ([self.system.systemInbetriebnahme compare:date] == NSOrderedDescending)
        return nil;

But this removes the case when they are both equal is there a way to compare dates with >= ?

Thank you

More details: I have a date taken from a double dimension array, and i have a date stored in core data(through date picker), and i go through a loop to compare the two dates with the rule that: Date in array must be greater or equal than input date stored in database.

Latest Edit:

I import a csv file which after parsing and formatting gives me two rows(one for number value and one for dates). Here I am interested in dates.

I store all these in an array and save after checking consistency of the data in this function:

for (NSArray * row in array) {


 // Handle import if there are at least two rows


if (row.count > 1) {

            dispatch_sync(dispatch_get_main_queue(), ^{
                // Try to import value,date formatted row
                double value = [row[0] doubleValue];
                NSDate * date = [dateFormatter dateFromString:row[1]];
               //else {

                    // Try to import date,value row

                    if (date && value != 0.0) {
                        [self addReading:value forDate:date];
                    }

In here i call the function addreading to check for errors for some rules and if everything is okey then i save the managedObject Context.

 if ([installationdatum compare:date] != NSOrderedAscending)
               { 
               UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil
                 message:@"installation date is bigger than data"
                                                                  delegate: nil
                                                         cancelButtonTitle:@"OK"
                                                         otherButtonTitles:nil] 

                    [alert show];
                   return nil;



               } else
               {  //Do nothing

               }

One rule for me is to get the first row element in the array and compare its date with an input stored already in the database which is the self.system.systemInbetriebnahme
After all this I list all the resulting array in a tableview, though value matching NSOrderedSame is never shown when it is equal to self.system.systemInbetriebnahme

回答1:

Simply check for not ascending order.

if ([self.system.systemInbetriebnahme compare:date] != NSOrderedAscending)
        return nil;

回答2:

Simple...

if ([date1 compare:date2] == NSOrderedDescending) {
    NSLog(@"date1 is later than date2");        

} else if ([date1 compare:date2] == NSOrderedAscending) {
    NSLog(@"date1 is earlier than date2");

} else {
    NSLog(@"dates are the same");

}

回答3:

NSDate *toDay = [[NSDate alloc]init];

NSLog(@"%@",toDay);

 NSLog(@"%@",yourSecondDate);

if ([toDay timeIntervalSinceDate:yourSecondDate] < 30.0f) 
 {
    NSLog(@"Do Something");
 }

回答4:

Well >= just means that they are !<, so you can check

if ([self.system.systemInbetriebnahme compare:date] != NSOrderedAscending)

回答5:

You could either check if the result is equal to both NSOrderedDescending and NSOrderedSame:

NSComparisonResult comparisonResult = [self.system.systemInbetriebnahme compare:date]
if (comparisonResult == NSOrderedDescending  || comparisonResult == NSOrderedSame)
        return nil;

Or just not match the one option left:

NSComparisonResult comparisonResult = [self.system.systemInbetriebnahme compare:date]
if (comparisonResult != NSOrderedAscending)
        return nil;

In your case I would go the later option, since you only have 3 options check against the one you don't want is easiest.

回答6:

I think this will help you. do something when one is less or equal than the other as you looking different case.

switch ([self.system.systemInbetriebnahme compare: date]) {
case NSOrderedAscending:
    // system date earlier then date
    break;
case NSOrderedSame:
    //  Same
    break;
case NSOrderedDescending:
    // system date later then date
    break;
}

回答7:

there is no direct comparision like >= but you can do it like this

NSComparisonResult compareStart = [date1 compare: selectedDate]; // date1 is 6/6/2011 00:00
NSComparisonResult compareEnd = [date2 compare: selectedDate];   // date2 is 9/6/2011 00:00

if ((compareStart == NSOrderedAscending) || (compareStart == NSOrderedSame)
&& (compareEnd == NSOrderedDescending))
{
// date is in the right range
}

or you simply compare

if ((compareStart == NSOrderedAscending) )
{
// date is in the right range
}

回答8:

To com[are two NSDate, this :

[[date1 earlierDate:date2] isEqualToDate: date1]

returns YES if the date1 is earlier than date2.

EDIT

if you want date1 >= date2 (later or equals to) use this condition :

([[date1 laterDate:date2] isEqualToDate: date1] || [date2 isEqualToDate:date1])

来源：https://stackoverflow.com/questions/18465502/ios-compare-two-less-or-equal-nsdates

标签

ios

objective-c

nsdate