基本用法

在 Swift 中实现正则表达式时有几个注意事项。

let letters = "abcdefg"
let pattern = "[a,b,c]"
let regEx = try NSRegularExpression(pattern: pattern, options: [])
let nsString = letters as NSString
let matches = regEx.matches(in: letters, options: [], range: NSMakeRange(0, nsString.length))
let output = matches.map {nsString.substring(with: $0.range)}
//output = ["a", "b", "c"]

为了获得支持所有字符类型的准确范围长度，必须将输入字符串转换为 NSString。

为了安全匹配模式，应将其包含在 do catch 块中以处理故障

let numbers = "121314"
let pattern = "1[2,3]"
do {
    let regEx = try NSRegularExpression(pattern: pattern, options: [])
    let nsString = numbers as NSString
    let matches = regEx.matches(in: numbers, options: [], range: NSMakeRange(0, nsString.length))
    let output = matches.map {nsString.substring(with: $0.range)}
    output
} catch let error as NSError {
    print("Matching failed")
}
//output = ["12", "13"]

正则表达式功能通常放在扩展或帮助程序中以分离关注点。