How to use NSRegular Expression and filter string array correctly in Swift

Question

Here is my question, I have a string array that contains a bunch of countries:

let myCountryStart = ["Africa/ABC", "America/BBC", "Asia/CBC", "Pacific/CBA", "Europe/CBB", "Indian/CAB"]

Is there have any solution to remove the specific words like 'Africa', 'America', 'Asia'...etc,. Let the output result looks like the below followings:

let myCountryEnd = ["ABC", "BBC", "CBC", "CBA", "CBB", "CAB"]

Here are my code for now...

let 1stReplace = myCountryStart.replacingOccurrences(of: "/", with: "", options: .literal)
let 2ndReplace = 1stReplace.replacingOccurrences(of: "Africa", with: "", options: .literal)
let 3rdReplace = 2ndReplace.replacingOccurrences(of: "Asia", with: "", options: .literal)

I know this is a stupid solution. Hence, I prefer to use NSRegular Expression. But I encountered a problem about String & String Array issue.

let target = myCountryStart
let regex = "/"
let RE = try? NSRegularExpression(pattern: "regex", options: .caseInsensitive)
let modified = RE?.stringByReplacingMatches(in: target, options: .reportProgress, range: nil, withTemplate: "") {
    return modified
}
let myCountryEnd = modified

Therefore, I got a warning about I cannot use this method on String array. What should I do to fix it?

Any suggestions or help will be greatly appreciated. Thanks from a Swift rookie.

myCountryStart seems to only have one element. Is that true? — Sweeper
– Sweeper, Commented May 25, 2020 at 7:59
What is outputStrin your old code? Why don't you use that, instead of myCountryStart in your new code? — Sweeper
– Sweeper, Commented May 25, 2020 at 8:01
It should be six elements of a string array. I forgot to revise it. — Spencer Reid
– Spencer Reid, Commented May 25, 2020 at 8:06

Wiktor Stribiżew · Accepted Answer · 2020-05-25 08:13:15Z

2

You may use .map and .replacingOccurrences using a regex like .*/ or ^[^/]*/:

let myCountryStart = ["Africa/ABC", "America/BBC", "Asia/CBC", "Pacific/CBA", "Europe/CBB", "Indian/CAB"]
let myCountryEnd = myCountryStart.map{ $0.replacingOccurrences(of: ".*/", with: "", options: [.caseInsensitive,.regularExpression]) }
print(myCountryEnd)
// => ["ABC", "BBC", "CBC", "CBA", "CBB", "CAB"]

The .*/ pattern will match any 0 or more characters other than line break chars, as many as possible, up to the last /.

The ^[^/]*/ pattern will match any chars other than / from the start of the string till the first /.

Note you do not need the .caseInsensitive option, I kept it to show how you may combine several options in the options argument.

answered May 25, 2020 at 8:13

Wiktor Stribiżew

631k41 gold badges502 silver badges632 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

How to use NSRegular Expression and filter string array correctly in Swift

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related