Can i do something like this in kotlin ```products sort a b kotlinlang #announcements

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Sergio Crespo Toubes

07/10/2018, 10:55 AM

Can i do something like this in kotlin?

products.sort {
            a,b -> }

Andreas Sinz

07/10/2018, 10:57 AM

what exactly are you trying to do?

Sergio Crespo Toubes

07/10/2018, 10:59 AM

i need to sort two elements by distance

and i have latitude and longitude variables

gildor

07/10/2018, 11:00 AM

Depends on case. There are sortedBy, sortedWith, sortBy, sortWith. extensions

sorted and sort versions are different, one returns copy of collection, another sorts mutable collection

probably you need something like:

products.sortWith(Comparator { a, b ->  })

Sergio Crespo Toubes

07/10/2018, 11:03 AM

thanks

gildor

07/10/2018, 11:03 AM

But if your collection element implements Comparable, you can just do something like:

products.sortBy { it.distance }

products.sortBy { it.location }

but distance or location must be Comparable

Sergio Crespo Toubes

07/10/2018, 11:04 AM

val productLocation = Location()
            productLocation.latitude = it.address!!.latitude
            productLocation.longitude = it.address!!.longitude
            mLocationManager.distanceTo(productLocation, androidLocation)

this was my solution

thank you

but it´s nice learn how to use comparator

gildor

07/10/2018, 11:05 AM

you can also convert location to distance (or some object with distance) using

map

and than sort just by distance. Because calculating distnace on each comparasion doesn’t looks like an efficient way to do that (you have much more comparisons than items in your list)

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