NSDateFormatter subtraction

Question

I have a datepicker for the field "From" and "To" and I want the result of the subtraction. for example: toValue-fromValue and the result would be in hours. How to do that?

albertamg · Accepted Answer · 2011-07-08T20:28:13.403

2

The difference of the two NSdate objects can be calculated using timeIntervalSinceDate:

NSTimeInterval diff = [toDate timeIntervalSinceDate:fromDate];

The result is given in seconds. Then, you calculate the hours like this:

NSInteger hours = diff / 3600;

edited Jul 08 '11 at 20:28

answered Jul 08 '11 at 20:22

albertamg

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It should be noted that NSTimeInterval is an alias for "double" -- a double-precision float. – Hot Licks Jul 08 '11 at 20:58
I am getting EXC_BAD_ACCESS. I tried with double diff=... but its not working either. – BlackM Jul 09 '11 at 08:33
@user776720 I think you have a memory management problem with your `NSDate` objects. Can you post the code? – albertamg Jul 09 '11 at 09:41
Fixed. I didnt retaining the toDate and fromDate. – BlackM Jul 09 '11 at 12:49

score 1 · Answer 2 · answered Jul 08 '11 at 20:23

If you have two NSDate objects you can compare them using the timeIntervalSinceDate method

NSDate* fromDate = //Get from date picker
NSDate* toDate = //Get from date picker
NSTimeInterval = [fromDate timeIntervalSinceDate:toDate];
NSInteger hours = timeInterval / 60*60; //60 seconds per minute, 60 minutes per hour

NSDateFormatter subtraction

2 Answers2