swift - 在 Swift 3 中，如何从包含许多此类字符的字符串中替换 URL 的单个字符？

Question

所以我有一个图像 URL:

https://images.gr-assets.com/books/1410762334m/135625.jpg

我想将第一个数字 block (1410762334) 后面的字母 "m" 更改为字母 "l"。

我尝试使用 replacingOccurrences(of: "m", with: "l", options: .literal, range: nil) ，正如预期的那样，它用 l 替换了所有 m，但事实并非如此。不工作。我知道这与范围有关，但我不确定将什么作为范围。请赐教:)

提前致谢!

Answer 1

为此，您应该使用NSRegularExpression。

• 首先，此代码搜索后跟字母 m 和斜线 (/) 的数值。
• 之后，它仅在该范围内搜索 m 并将其替换为 l。

<小时/>

let urlString: NSString = "https://images.gr-assets.com/books/1410762334m/135625.jpg"

do {
    let regex = try NSRegularExpression(pattern: "[0-9]m/", options: .caseInsensitive)

    let fullRange = NSMakeRange(0, urlString.length)
    let matchRange = regex.rangeOfFirstMatch(in: urlString as String, options: [], range: fullRange)

    let modString = urlString.replacingOccurrences(of: "m", with: "l", options: .caseInsensitive, range: matchRange)
} catch let error {
    //NSRegularExpression threw an error; handle it properly
    print(error.localizedDescription)
}

swift 4

let urlString = "https://images.gr-assets.com/books/1410762334m/135625.jpg"

do {
    let regex = try NSRegularExpression(pattern: "[0-9]m/", options: .caseInsensitive)

    let fullRange = NSMakeRange(0, urlString.count)
    let matchRange = regex.rangeOfFirstMatch(in: urlString, options: [], range: fullRange)

    let modString = urlString.replacingOccurrences(of: "m", with: "l", options: .caseInsensitive, range: Range(matchRange, in: urlString))
} catch let error {
    //NSRegularExpression threw an error; handle it properly
    print(error.localizedDescription)
}