規(guī)則：

手機號： 根據(jù)位數(shù)隱藏四位

(example: 五位：****5；七位：1****67；九位：12****78； 十一位：123****8910 )

郵箱： @符號前只展示第一位和最后一位

(example：1*****6@qq.com)

    func hidePhoneNumber(number: String) -> String {
        
        if number.count < 5 {
            var str = ""
            for _ in 0 ..< number.count {
                str += "*"
            }
            return str
        } else {
            //替換一段內(nèi)容，兩個參數(shù)：替換的范圍和用來替換的內(nèi)容
            let start = number.index(number.startIndex, offsetBy: (number.count - 5) / 2)
            let end = number.index(number.startIndex, offsetBy: (number.count - 5) / 2 + 4)
            let range = Range(uncheckedBounds: (lower: start, upper: end))
            return number.replacingCharacters(in: range, with: "****")
        }
    }
    
    func hideEmail(email: String) -> String {
        var mail = email
        let arraySubstrings: [Substring] = mail.split(separator: "@")
        let arrayStrings: [String] = arraySubstrings.compactMap { "\($0)" } // i將Substring轉(zhuǎn)為string
        var str = ""
        if arrayStrings[0].count < 3 {
            for _ in 0 ..< arrayStrings[0].count {
                str += "*"
            }
            return str + arrayStrings[1]
        } else {
        for _ in 0 ..< arrayStrings[0].count - 2 {
            str += "*"
        }
            let start = mail.index(mail.startIndex, offsetBy: 1)
            let end = mail.index(mail.startIndex, offsetBy: arrayStrings[0].count - 1)
            let range = Range(uncheckedBounds: (lower: start, upper: end))
            mail.replaceSubrange(range, with: str)
            return mail
        }
        
    }

使用：

self.hidePhoneNumber(number: phone)
self.hideEmail(email: email)

注意：
代碼不是很完美，位數(shù)太少的時候會出錯，實際項目中需要有位數(shù)限制