How to fetch safety value from String in Swift iOS? - ios

Question

I have EKParticipant object with description looks like:
item description: EKAttendee <0x1c0b7d90> {UUID = 116B99AB9-41AC-4741-A288-B67172298625; name = Snaggy Snags; email = snaggy#gmail.com; status = 4; role = 1; type = 1}
How to safety split this string to Dictionary in order to fetch after email key value?
This is what I did so far:
extension String {
func split(splitter: String) -> Array<String> {
let regEx = NSRegularExpression(pattern: splitter, options: NSRegularExpressionOptions(), error: nil)!
let stop = "SomeStringThatYouDoNotExpectToOccurInSelf"
let modifiedString = regEx.stringByReplacingMatchesInString(self, options: NSMatchingOptions(), range: NSMakeRange(0, countElements(self)), withTemplate: stop)
return modifiedString.componentsSeparatedByString(stop)
}
func removeCharsFromEnd(count:Int) -> String{
let stringLength = countElements(self)
let substringIndex = (stringLength < count) ? 0 : stringLength - count
return self.substringToIndex(advance(self.startIndex, substringIndex))
}
}
var str = "item description: EKAttendee <0x1c0b7d90> {UUID = 16B99AB9-41AC-4742-A288-B67172299625; name = Snaggy Snags; email = snaggy#gmail.com; status = 4; role = 1; type = 1}"
var newStr = str.split("\\{")[1]
newStr = newStr.removeCharsFromEnd(1)
So now newStr equals:
UUID = 16B99AB9-41AC-4741-A288-B67172298625; name = Snaggy Snags; email = snaggy#gmail.com; status = 4; role = 1; type = 1
What next?
Thanks,

Answer 1

You can use componentsSeparatedByString method to extract your elements as follow:
extension String {
var elements:(udid: String, name: String, email: String, status: Int, role: Int, type: Int) {
let components = componentsSeparatedByString("; ")
if components.count == 6 {
let udid = components[0].componentsSeparatedByString(" = ").last ?? ""
let name = components[1].componentsSeparatedByString(" = ").last ?? ""
let email = components[2].componentsSeparatedByString(" = ").last ?? ""
let status = components[3].componentsSeparatedByString(" = ").last ?? ""
let role = components[4].componentsSeparatedByString(" = ").last ?? ""
let type = components[5].componentsSeparatedByString(" = ").last ?? ""
return (udid, name, email, (status as NSString).integerValue, (role as NSString).integerValue, (type as NSString).integerValue)
}
return ("","","",0,0,0)
}
}
let input = "UUID = 16B99AB9-41AC-4741-A288-B67172298625; name = Snaggy Snags; email = snaggy#gmail.com; status = 4; role = 1; type = 1"
let result = input.elements // (.0 "16B99AB9-41AC-4741-A288-B67172298625", .1 "Snaggy Snags", .2 "snaggy#gmail.com", .3 4, .4 1, .5 1, .6 "UUID = 16B99AB9-41AC-4741-A288-B67172298625; name = Snaggy Snags; email = snaggy#gmail.com; status = 4; role = 1; type = 1")
println(result.udid) // "16B99AB9-41AC-4741-A288-B67172298625"
println(result.name) // "Snaggy Snags"
println(result.email) // "snaggy#gmail.com"
println(result.status.description) // "4"
println(result.role.description) // "1"
println(result.type.description) // "1"
You can also use String's method hasPrefix to make sure you are grabbing the right info from your elements even if they return unordered as follow:
extension String {
var elements:(udid: String, name: String, email: String, status: Int, role: Int, type: Int) {
let components = componentsSeparatedByString("; ")
var udid = "", name = "", email = "", status = 0, role = 0, type = 0
for item in components {
println(item)
if item.hasPrefix("UUID = "){
udid = item.substringWithRange(Range(start: advance(item.startIndex, 7), end: item.endIndex))
}
if item.hasPrefix("name = "){
name = item.substringWithRange(Range(start: advance(item.startIndex, 7), end: item.endIndex))
}
if item.hasPrefix("email = "){
email = item.substringWithRange(Range(start: advance(item.startIndex, 8), end: item.endIndex))
}
if item.hasPrefix("status = "){
status = (item.substringWithRange(Range(start: advance(item.startIndex, 9), end: item.endIndex)) as NSString).integerValue
}
if item.hasPrefix("role = "){
role = (item.substringWithRange(Range(start: advance(item.startIndex, 7), end: item.endIndex)) as NSString).integerValue
}
if item.hasPrefix("type = "){
type = (item.substringWithRange(Range(start: advance(item.startIndex, 7), end: item.endIndex)) as NSString).integerValue
}
}
return (udid, name, email, status, role, type)
}
}
let input = "UUID = 16B99AB9-41AC-4741-A288-B67172298625; name = Snaggy Snags; email = snaggy#gmail.com; status = 4; role = 1; type = 1"
let elements = input.elements // (.0 "16B99AB9-41AC-4741-A288-B67172298625", .1 "Snaggy Snags", .2 "snaggy#gmail.com", .3 4, .4 1, .5 1)
let udid = elements.udid // "16B99AB9-41AC-4741-A288-B67172298625"
let name = elements.name // "Snaggy Snags"
let email = elements.email // "snaggy#gmail.com"
let status = elements.status.description // "4"
let role = elements.role.description // "1"
let type = elements.type.description // "1"

Answer 2

Here is method that fetches email or returns nil if something goes wrong:
func fetchEmailIfExists(str:String) -> String?{
var email:String?
for item:String in str.split(";"){
if item.contains("email"){
var emailPart = item.trim()
if emailPart.componentsSeparatedByString("=").first?.trim() == "email" {
if let temp:String = emailPart.componentsSeparatedByString("=").last?.trim(){
return temp
}
}
}
}
return email
}
Helpers
extension String {
func split(splitter: String) -> Array<String> {
let regEx = NSRegularExpression(pattern: splitter, options: NSRegularExpressionOptions(), error: nil)!
let stop = "SomeStringThatYouDoNotExpectToOccurInSelf"
let modifiedString = regEx.stringByReplacingMatchesInString(self, options: NSMatchingOptions(), range: NSMakeRange(0, countElements(self)), withTemplate: stop)
return modifiedString.componentsSeparatedByString(stop)
}
func trim() -> String {
return self.stringByTrimmingCharactersInSet(.whitespaceAndNewlineCharacterSet())
}
func contains(find: String) -> Bool{
return self.rangeOfString(find) != nil
}
}

Answer 3

This a perfect use case for NSScanner. The stringToDictionary takes a String like yours and returns a dictionary of [String: String]. You can use it for any string in your format, regardless of the amount of key/value pairs. However it will break down when the values contain semicolons or equal signs.
let string = "item description: EKAttendee <0x1c0b7d90> {UUID = 116B99AB9-41AC-4741-A288-B67172298625; name = Snaggy Snags; email = snaggy#gmail.com; status = 4; role = 1; type = 1}"
var dictionary = stringToDictionary(string)
func stringToDictionary(input: String) -> [String: String] {
var output = [String: String]()
let scanner = NSScanner(string: input)
let separatingCharacters = NSCharacterSet(charactersInString: ";}")
scanner.scanUpToString("{", intoString: nil)
scanner.scanString("{", intoString: nil)
var key: NSString?, value: NSString?
while !scanner.atEnd {
scanner.scanUpToString(" =", intoString: &key)
scanner.scanString("= ", intoString: nil)
scanner.scanUpToCharactersFromSet(separatingCharacters, intoString: &value)
scanner.scanCharactersFromSet(separatingCharacters, intoString: nil)
if let key = key as? String, value = value as? String {
output[key] = value
}
}
return output
}