core data averages

[psilocybin]

how can i grab a certain amount of values in an entity..i have an entity for values and a entity for the date
i want to grab a weeks worth of values and a month and a year

any help thanks

[sneaky]

you're asking 2 questions really.
Yes you can set a limit to the number of objects returned by your fetch request but that's not what you want to do.

You want to set up a predicate so that only results between 2 dates are returned. something along the lines of

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"date > %@ AND date < %@", someOldDate, [NSDate date]];
[fetchRequest setPredicate:predicate];

This will return all objects where the date of the object falls between somOldDate and now.

[psilocybin]

ah thanks...ill work on that

[psilocybin]

is there a resource i can read to interpret this into a pickerview with fetching certain values depending on whats selected? would i have to execute a fetch request for each property in the pickeriew?

[sneaky]

Originally Posted by psilocybin

is there a resource i can read to interpret this into a pickerview with fetching certain values depending on whats selected? would i have to execute a fetch request for each property in the pickeriew?

well....
What have you got in your pickerview???
usually if you have a pickerview you'd have 1 array per spinner. you may have to do one fetch per spinner depending on what your data looks like.

But I really can't tell without more information

[psilocybin]

I have 1 pickerview it contains 1 week, 2 weeks, 3 weeks. Depending on the choice I will be calculating the average of the values within the givin time

[sneaky]

So in your picker delegate you will need to create a date to use for the fetch and then do what you need to do with the data

[psilocybin]

Can you please explain a bit better? I'm still in the middle stages of learning

[sneaky]

Right, so you spin the picker to 2weeks. Your picker has a delegate method, the delegate will get called when the value of the picker change.

Then you will have to create 2 dates, a from and a to date.

I don't know what you want to do with your data but using the from and the to date above you should be able to fetch the data you're after.

I'm not sure after that what you need help with. Be specific.

[psilocybin]

BasicLly I just need help with that delegate method. I'm getting the values from those days and calculating the sum

[sneaky]

So look up uipickerview delegate protocol and check what methods could apply to what you want to do. Hint, you'll get an index.

You will have to create the dates. Loop up how to create a date from components. You can use an offset from the current date.

I've used a good few keywords here now. Google is your friend