swift - Find backward in string first substring that belongs to a set (regex?) -


i have set of string set , find first occurrence of 1 string of set substring of string string. search in backward direction position (an integer).

i have written code uses loop able write in more compact way, maybe regex needed.

can please me?

edit. temporary solution: currentposition integer value given nstextview, command string manipulating, doing checking if character after 1 @ currentposition " " or if last of string command. in such cases extrapolate substring of command spaces currentposition nearest (in backward direction) delimiter (defined in code).

what in question called set here array of string , represented separators, string here command, , position here currentposition.

let currentposition = self.selectedrange().location let currentpositionindex = command.index(command.startindex,offsetby: currentposition) if(currentposition == command.characters.count || command[currentpositionindex] == " ")  {     let separatorsstring = " .,:~/!+=\\;/?"     let separators = separatorsstring.characters     //todo: use regex in order clean code     var nearestseparatorposition = command.startindex     outerloop: in stride(from: currentposition - 1, to: -1, by: -1) {         separator in separators {             let index = command.index(command.startindex, offsetby: i)             if(command[index] == separator) {                 nearestseparatorposition = command.index(index, offsetby: 1)                 break outerloop             }         }     }     swift.print("current word index = (\(command.distance(from: command.startindex, to: nearestseparatorposition)),\(command.distance(from: command.startindex, to: currentpositionindex)))")     let currentword = command.substring(with: nearestseparatorposition ..< currentpositionindex)

i'm not sure if have things flipped around, based un understanding of question do:

func findfirstcontaining(needle item: string, in haystack: [string]) -> string? {      let stringranges: [range<string.index>] = haystack.flatmap { return item.range(of: $0) } .sorted { $0.lowerbound < $1.lowerbound }     if let range = stringranges.first {         return item.substring(with: range)     }     else {         return nil     } }  let testset: set<string> = ["test", "string", "set"]  let needle = "this test"  // evaluates "test" let result = findfirstcontaining(needle: needle, in: testset.sorted())  let reversedresult = findfirstcontaining(needle: needle, in: testset.sorted().reversed())

this inefficient, i'm not sure problem you're trying solve.


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