如何为以@开头或以？开头的字符串匹配编写正则表达式？

Question

如何为以#开头@或结尾的字符串匹配编写正则表达式,.我正在寻找JavaScript中的代码.

Answer 1

RegEx解决方案将是:

var rx = /(^@|,$)/;
console.log(rx.test(""));    // false
console.log(rx.test("aaa")); // false
console.log(rx.test("@aa")); // true
console.log(rx.test("aa,")); // true
console.log(rx.test("@a,")); // true

但为什么不简单地使用字符串函数来获取第一个和/或最后一个字符:

var strings = [
  "",
  "aaa",
  "@aa",
  "aa,",
  "@a,"
];
for (var i = 0; i < strings.length; i++) {
  var string = strings[i],
    result = string.length > 0 && (string.charAt(0) == "@" || string.slice(-1) == ",");
  console.log(string, result);
}

Answer 2

对于以@开头或以逗号结尾的字符串,正则表达式如下所示:

/^@|,$/

或者你,可以这样做:

if ((str.charAt(0) == "@") || (str.charAt(str.length - 1) == ",")) {
    // string matched
}