How to Replace specific range of string with a character?

user_8425034 0
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I'm using swift in my project. I want to change a specific range of string with a character. for example I have a string "1234567890" and I want to change characters in range, location 5 and length 3 to "". the out put should be "12345***90".

I see a ways for doing this by converting string to NSString and using this function:

stringByReplacingCharactersInRange

but is there any better way? a swift way :)

swift string
2 Answers

There's a way to write that in Swift in one line:

let stringA = "1234567890"
let stringB = String(stringA.enumerated().map { !(5...7).contains($0) ? $1 : "*" })
let stringC = String(stringA.enumerated().compactMap { !(5...7).contains($0) ? $1 : $0 == 5 ? "*" : nil })

print(stringB) // "12345***90\n"
print(stringC) // "12345*90\n"

Just to add some explanation: We enumarate the String so we can use the indexes to map the Characters based on their position on the String. On the closure, $0 corresponds to the offset and $1 to the Character on the iteration. It could also be written as $0.offset and $0.element, respectively.
On the second example with stringC, where it replaces with only one *, we replace the Character in position 5 with the * and the rest with nil, and the compactMap will return all of the non-nil results.

user_5645320

Maybe this?

var myString = "1234567890"
let startIndex = myString.index(myString.startIndex, offsetBy: 5)
let endIndex = myString.index(startIndex, offsetBy: 3)
myString.replaceSubrange(startIndex..<endIndex, with: "***")
    
print("\(myString)")

Write an extension if necessary

extension String {

    mutating func replaceSubString(startAt: Int, offsetBy: Int, with newString: String) {
        let startIndex = self.index(self.startIndex, offsetBy: startAt)
        let endIndex = self.index(startIndex, offsetBy: offsetBy)
        self.replaceSubrange(startIndex..<endIndex, with: newString)
    }
    
}

and you use it like this:

var myString = "1234567890"
myString.replaceSubString(startAt: 5, offsetBy: 3, with: "***")
print("\(myString)")
user_10047020
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