从Swift中的字符串中删除某个字符之后的所有字符 [英] Delete all characters after a certain character from a string in Swift

问题描述

我有一个 textField，我想删除某个字符后的所有字符.

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

例如，如果我在 textField 中有单词 Orange 并且我想删除 n 之后的所有字符，我想得到 Ora 删除后.

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.

如何在 Swift 中删除字符串中某个字符后的所有字符?

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

谢谢

推荐答案

可以使用StringProtocol方法range(of string:)，得到结果范围lowerBound，创建一个带有它的 PartialRangeUpTo 并为原始字符串添加下标:

You can use StringProtocol method range(of string:), get the resulting range lowerBound, create a PartialRangeUpTo with it and subscript the original string:

Swift 4 或更高版本

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"
}

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