Match substring with another substring in Swift

Question

I am working on Swift 4.

The requirement: I have a string:

var inputString = "Today is very bright day"

I have a file containing key value pairs for strings.

{
    "Birthday": ["brand day", "burn day", "bright day", "brick daya"],
    "Temporary": ["tempora", "temporar", "tempura"]
}

The math needed: In the app, if the inputString is "Today is very bright day", I need to check if this string contains any of the values from the key-value pair file and replace the occurrence with the key.

e.g: In above example: inputString = "Today is very bright day" match it with the file. replace bight day with birthday so that the inout string becomes inputString = "Today is very birthday".

Is there any way to do this? The key-value file could be big.

Wouldn't it make more sense to invert the Dictionary? Map the words you're searching for, to the words you're replacing them with — Alexander
– Alexander, Commented Jun 15, 2018 at 17:14
Actually, since some of these terms are multiple words, you wouldn't get that much benefit from doing what I just mentioned above. I was thinking you could split on spaces/punctuation to get words, and query the dict for each word. That wouldn't work for doing multi-word matches. — Alexander
– Alexander, Commented Jun 15, 2018 at 17:24

Abdelahad Darwish · Accepted Answer · 2018-06-15 20:40:30Z

1

You can use brute force solution it will be 2 for loop , i work on way to enhance it

  var inputString = "Today is very bright day"

        let file  = ["Birthday":["brand day", "burn day", "bright day", "brick daya"],"Temporary": ["tempora", "temporar", "tempura"]]

        file.forEach { (key,value) in
            value.forEach({ (item) in
               inputString =  inputString.replacingOccurrences(of: item, with: key)
            })
        }

        print(inputString)

answered Jun 15, 2018 at 20:40

Abdelahad Darwish

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1 Comment

BlackPearl12 Over a year ago

This one looks more feasible, but time consuming with iterating over each values. Lets integrate this and I will see. Thank you. @Abdelahad

Jeffrey Chen · Accepted Answer · 2018-06-15 16:31:40Z

0

I think you will have to iterate through each list of each key value pairing no matter what, but here is a basic way to do replace substrings.

import Foundation

let replacer = "Birthday"
let replacees = ["brand day", "burn day", "bright day", "brick daya"]

var inputString = "Today is very bright day"

for phrase in replacees {
    inputString = inputString.replacingOccurrences(of: phrase, with: replacer)
}

print(inputString) //should print "Today is very birthday"

answered Jun 15, 2018 at 16:31

Jeffrey Chen

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4 Comments

BlackPearl12 Over a year ago

This looks achievable. Let me implement this and see. The solution here works fine for just one pair of replacer and replacees. As I mentioned in the question. I will have multiple replacers and multiple replacees. How to go about that?

Jeffrey Chen Over a year ago

I'm not exactly sure how you are storing your [replacer, replacees] pairings, but what you can do is just put translate the above code to a function and then just use a for-loop to apply each one of the replacer-replacees pairings. func f(replacer: String, replacees: [String], inputString: String) -> String { // insert the above code into here }

Jeffrey Chen Over a year ago

Oh wait I didn't see that you were storing it as a dictionary. So you will need a nested for loop (or equivalent), where you do: for key in keyValuePairings {// above code} and then you use key as replacer, and use keyValuePairings[key] as replacees.

Jeffrey Chen Over a year ago

It is essentially is just Abdelahad Darwish's solution

André · Accepted Answer · 2018-06-15 18:29:53Z

0

I cant't figure anyway to achieve what you want without iterating through your key-value list, but here is a solution. I'm not sure if it will be efficient, but you may try it.

        if let path = Bundle.main.path(forResource: "fileName", ofType: "json") {
            do {
                let data = try Data(contentsOf: URL(fileURLWithPath: path), options: .mappedIfSafe)
                let jsonResult = try JSONSerialization.jsonObject(with: data, options: .allowFragments)

                if let keyValueArray = jsonResult as? [String: [String]]{
                    var inputString = "Today is very bright day"

                    for (key, value) in keyValueArray {
                        let regex = "\\b" + value.joined(separator: "|\\b")

                        inputString = inputString.replacingOccurrences(of: regex, with: key, options: .regularExpression, range: nil)
                    }

                    print(inputString)
                }
            } catch {
                return
            }
        }

answered Jun 15, 2018 at 18:29

André

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1 Comment

BlackPearl12 Over a year ago

Thanks. I will definitely try it.

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