Count the number of lines in a Swift String

Question

After reading a medium sized file (about 500kByte) from a web-service I have a regular Swift String (lines) originally encoded in .isolatin1. Befor

Answer 1

As I did not find a generic way to count newlines I ended up just solving my problem by iterating through all the characters using

let linesCount = text.reduce(into: 0) { (count, letter) in
     if letter == "\r\n" {      // This treats CRLF as one "letter", contrary to UnicodeScalars
        count += 1
     }
}

I was sure this would be a lot faster than enumerating lines for just counting, but I resolved to eventually do the measurement. Today I finally got to it and found ... that I could not have been more wrong.

A 10000 line string counted lines as above in about 1.0 seconds , but counting through enumeration using

var enumCount = 0
text.enumerateLines { (str, _) in
    enumCount += 1
}

only took around 0.8 seconds and was consistently faster by a little more than 20%. I do not know what tricks the Swift engineers hide in their sleves, but they sure manage to enumerateLines very quickly. This just for the record.