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Akos Turi
7,517 Pointschallenge
protocol PrefixContaining { func hasPrefix(_ prefix: String) -> Bool }
extension String: PrefixContaining { func hasPrefix(_ prefix: String) -> Bool { var matching = false
if prefix.characters.count <= self.characters.count {
let distance = self.index(self.startIndex, offsetBy: prefix.characters.count)
if prefix == self.substring(to: distance) {
matching = true
}
}
return matching
}
}
extension Array where Element: PrefixContaining {
func filter(byPrefix prefix: String) -> [Element] {
var newArray: [Element] = []
for item in self {
if item.hasPrefix(prefix) {
newArray.append(item)
}
}
return newArray
}
}
let test = ["akos", "ba", "ca", "akosturi", "aki"] let result = test.filter(byPrefix: "akos")
probably this is not the best solution, but it works for me, although i got compiler error in the treehouse compiler. In my Xcode i tried it with many times and it works fine. Thanks for the help in advance.
1 Answer
Jason Tjahja
8,668 PointsHello, just a reminder String has a instance method which is hasPrefix( ) that takes specific prefix, also return a boolean value of true if the string has the prefix, so... you can make less effort to find out your string has specific prefix rather than code it in hard way..