on Wed Jun 08 2016, Dave Abrahams <swift-evolution@swift.org> wrote:
> on Wed Jun 08 2016, gadiraju praneeth <swift-evolution@swift.org> wrote: > >> Many times, I came across a scenario where I had to filter an array with a >> condition and filter the same array with opposite of that condition. For >> example: >> >> let values = [2, 4, 3, 5, 6, 9] >> >> let divisibleByTwo = values.filter { $0 % 2 == 0 } >> let notDivisibleByTwo = values.filter { $0 % 2 != 0 } >> >> Is there a way currently where we can filter the array into two arrays >> based on a condition? > > Well, you need a stable partition for this if you care about ordering > (see > https://github.com/apple/swift/blob/master/test/Prototypes/Algorithms.swift#L299) > but then you can do > > var parts = values > let mid = values.stablePartition { $0 % 2 == 0 } > let divisibleByTwo = parts.prefix(upTo: mid) > let notDivisibleByTwo = parts.suffix(from: mid) > > Nate Cook has an enhancement to the result of stablyPartitioned in that > prototype that would let you write: > > let parts = values.stablyPartitioned { $0 % 2 == 0 } > let divisibleByTwo = parts.prefix(upTo: parts.partitionPoint) > let notDivisibleByTwo = parts.suffix(from: parts.partitionPoint) Hmm, come to think of it, Nate, maybe there should also be a more convenient way to get the two partitions from the result. -- Dave _______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution