Delete all characters after a certain character from a string in Swift [duplicate]

问题

I have a textField and I would like to remove all character after a certain character.

For instance if what I have in the textField is the word Orange and I want to remove all characters after the n I would like to get Ora after the deletion.

How can I delete all characters after a certain character from a string in Swift?

Thanks

回答1:

You can use rangeOfString and substringToIndex to its startIndex as follow:

Swift 2

let word = "orange"
if let index = word.rangeOfString("n")?.startIndex {
    print(word.substringToIndex(index))  // "ora"
}

Swift 3

let word = "orange"
if let index = word.range(of: "n")?.lowerBound {
    print(word.substring(to: index))  // "ora"
}

Swift 4

let word = "orange"
if let index = word.range(of: "n")?.lowerBound {
    let substring = word[..<index]                 // "ora"
    // or  let substring = word.prefix(upTo: index) // "ora"
    // (see picture below) Using the prefix(upTo:) method is equivalent to using a partial half-open range as the collection’s subscript. 
    // The subscript notation is preferred over prefix(upTo:).

    let string = String(substring)
    print(string)  // "ora"
}

回答2:

You could do it like this:

guard let range = text.rangeOfString("Your String or Character here") else {
    return the text 
}

return text.substringToIndex(range.endIndex)
// depending on if you want to delete before a certain string, you would use range.startIndex

来源：https://stackoverflow.com/questions/39184984/delete-all-characters-after-a-certain-character-from-a-string-in-swift

标签

swift

string

nsstring

uitextfield