swift - ios 字符串替换为 * 最多 4 个

Question

我想显示一个除最后四位数字(如帐号)外全部为星号的数字。我曾尝试过将最后四位数字显示为 ****。这是我的代码。

let letters = "987654321"
let start = letters.endIndex;
let end = letters.index(letters.endIndex, offsetBy: -4);
let value = "****"
let result = letters.replacingCharacters(in: end..<start, with: value)
print(result)

Answer 1

此解决方案根据长度使用 String(repeating:count:) 创建星号字符串

let letters = "987654321"
let end = letters.index(letters.endIndex, offsetBy: -4)
let value = String(repeating: "*", count: letters.count-4)
let result = letters.replacingCharacters(in: ..<end, with: value)
print(result)

如果字符串的长度可能低于 4，请使用 limitedBy 参数并检查 nil:

if let end = letters.index(letters.endIndex, offsetBy: -4, limitedBy: letters.startIndex) { ...