Avoid multiplying of values while appending in object - swift

Question

I would like to ask how to corret my issue. I just simply append some "portals" to a depending country. EACH "portal" which comes more than once, I dont want to append.
I have following class definitions:
class cls_main{
var countries:[cls_country]!
init() {
countries = [cls_country]()
}
// "add Country"
func addCountry(iCountry:cls_country) {
countries.append(iCountry)
}
}
class cls_country{
var countryName:String!
var portals:[cls_portal]!
init() {
portals = [cls_portal]()
}
// "add Portal"
func addPortal(portName:String) {
var tmpPortal = cls_portal()
tmpPortal.portalName = portName
println("-->Input Portal: \(tmpPortal.portalName)")
if portals.count == 0 {
portals.append(tmpPortal)
} else {
for port in portals {
if port.portalName == portName {
println("SAME INPUT, DONT SAVE")
} else {
portals.append(tmpPortal)
}
}
}
}
func arrayCount(){
println("Portals : \(portals.count)")
}
}
class cls_portal{
var portalName:String!
}
And so I will call it:
var MAIN = cls_main()
var country = cls_country()
country.countryName = "USA"
country.addPortal("Dance")
country.addPortal("Dance") // Should not be appended...
country.addPortal("Hike")
country.addPortal("Swim")
country.addPortal("Play")
MAIN.addCountry(country)
country = cls_country()
After adding the values Im looping over the values and print them. The result would be like this:
Loop:
for country in MAIN.countries {
println("COUNTRY: \(country.countryName)")
if country.countryName == "USA" {
for portal in country.portals {
println(" -> PORTAL : \(portal.portalName)")
}
country.arrayCount()
}
}
Result:
-->Input Portal: Dance
-->Input Portal: Dance
SAME INPUT, DONT SAVE
-->Input Portal: Hike
-->Input Portal: Swim
-->Input Portal: Play
COUNTRY: USA
-> PORTAL : Dance
-> PORTAL : Hike
-> PORTAL : Swim
-> PORTAL : Swim
-> PORTAL : Play
-> PORTAL : Play
-> PORTAL : Play
-> PORTAL : Play
Portals : 8
So why every and each portal will be multiplying at the end? Thank you very much.

Answer 1

In your search loop, you are deciding after looking at each element whether tmpPortal is in your portals or not. You need to potentially look at all of the items before you can make that decision. Add a variable found to note that it has been found. You can break out of the loop once you've found the item.
if portals.count == 0 {
portals.append(tmpPortal)
} else {
var found = false
for port in portals {
if port.portalName == portName {
println("SAME INPUT, DONT SAVE")
found = true
// found it, stop searching
break
}
}
if !found {
portals.append(tmpPortal)
}
}

Answer 2

If you are using Swift 1.2 a better solution to this would by using Set so you wont need addPortal method at all. Set offers almost the same functionality as array but it simply does not store same values. Be aware that in order to make it work with set your cls_portal class must adopt hashable and equitable protocols
A set stores distinct values of the same type in a collection with no defined ordering. You can use sets as an alternative to arrays when the order of items is not important, or when you need to ensure that an item only appears once.

Answer 3

You’re looping multiple times over the array, checking it. But for every element that isn’t a match, you are inserting the portal. So when there are 3 other non-matching elements, you insert a portal 3 times.
Try replacing your inner loop (everything from if portals.count == all the way down to the end of the else) with this:
if !contains(portals, { $0.portalName == portName }) {
portals.append(tmpPortal)
}
contains is a function that checks if a collection (like your array of portals) contains an entry that matches a certain criteria. The criteria is determined by a closure, in this case one that checks if the element’s portal name matches the one you’re checking for. Try reading this link if you’re not familiar with closures – they can be very helpful in Swift.
P.S. there are a few other things in your code you might want to reconsider. For example, it’s best to avoid using implicitly-unwrapped optionals (i.e. types with a ! after them) like this. Implicit optionals are in Swift for some very specific purposes, which it doesn’t look like apply in your code. Especially not with arrays - better to just make the array empty on initialization. But also, if it makes no sense to have a portal without a country name, you make it part of the initializer.
So instead of this:
class cls_country{
var countryName:String!
var portals:[cls_portal]!
init() {
portals = [cls_portal]()
}
}
// and in use:
var tmpPortal = cls_portal()
tmpPortal.portalName = portName
you could write this:
class cls_country {
var portals = [cls_country]()
// consider let not var if a country will never
// need to change its name:
let countryName: String
init(countryName: String) {
self.countryName = countryName
//no need to initialize portals in init
}
}
// then later, in use:
var tmpPortal = cls_portal(countryName: portName)