关于大括号的Javascript正则表达式问题

Question

我编写了以下程序

var textRegEx = /.{1,3}/g;
var text = "AUZ01A1";
var woohooMatch = text.match(textRegEx);
var finalResult = woohooMatch.join(' - ')
console.log(finalResult);

给出如下输出:

Output:
AUZ - 01A - 1

我希望输出是AUZ - 01 - A1。我如何改变textRegEx来实现这一点?我尝试了(2,3}和其他一些东西，但它不起作用。我是javascript和regex的新手。你能帮帮我吗?

Answer 1

您可以使用()组来匹配3,2,2个字符的模式:

var text = "AUZ01A1";
var textRegEx = /(.{3})(.{2})(.{2})/;
var woohooMatch = text.match(textRegEx);
var [ , ...matches] = woohooMatch;
var finalResult = matches.join(' - ');

console.log(finalResult);

Answer 2

用简单的switch语句区分6/7、8和其他情况:

function format(string) {
switch (string.length) {
case 6:
case 7:
return string.match(
/^(.{2,3})(.{2})(.{2})$/
).slice(1).join(' - ');
break;
case 8:
return string.match(
/^(.{7})(.)$/
).slice(1).join(' - ');
default:
return string;
}
}

或者，如果您喜欢在简洁函数中使用复杂的正则表达式:

function format(string) {
const match = string.match(/^(?=.{6,8}$)(?:.{7}|.{2,3})(?=(.{1}$|.{2})(.{2})?$)/);
return match ? (match[2] ? match : match.slice(0, -1)).join(' - ') : string;
}

对正则表达式的解释，其余部分留给读者作为练习:

^                # Match at the beginning of string
(?=.{6,8}$)      # a string of 6, 7 or 8 characters long, which consists of
(?:.{7}|.{2,3})  # a capturing group of either 7 or 2 to 3 characters
(?=              # followed by
(.(?:.|$))     # a second capturing group of a character followed by another or the end of string
(.{2})?        # and an optional capturing group of two characters.
$              # right before the end of string.
)                #

在regex101.com上试试。

试一试:

function format1(string) {
switch (string.length) {
case 6:
case 7:
return string.match(
/^(.{2,3})(.{2})(.{2})$/
).slice(1).join(' - ');
break;
case 8:
return string.match(
/^(.{7})(.)$/
).slice(1).join(' - ');
default:
return string;
}
}
function format2(string) {
const match = string.match(/^(?=.{6,8}$)(?:.{7}|.{2,3})(?=(.{1}$|.{2})(.{2})?$)/);
return match ? (match[2] ? match : match.slice(0, -1)).join(' - ') : string;
}
// Test cases
const strings = [...'1234567890'].map(
(_, i, a) => a.slice(0, i + 1).join('')
);
console.log(strings.map(format1));
console.log(strings.map(format2));

.as-console-wrapper {
max-height: 100% !important;
}

Answer 3

对于您的格式，您可以使用捕获组的替代。

然后在结果中，删除完整匹配并使用-

连接捕获组注意.匹配任何字符。如果只想匹配大写字符或数字，可以使用字符类[A-Zd]

^(?:(.{2,3})(..)(..)|(.)(.{7}))$

• ^起始字符串
• (?:备选项的非捕获组
  • (.{2,3})(..)(..)3个捕获组，其中第一个组有2或3个字符
  • |或
  • (.)(.{7})2个捕获组，其中第一个组有一个字符，第二个组有7个字符
• )关闭非捕获组
• $字符串结束

Regex演示

const regex = /^(?:(.{2,3})(..)(..)|(.)(.{7}))$/gm;
const s = `AUZ01A
AUZ01A1
AUZ01A11`;
for (const match of s.matchAll(regex)) {
const result = match.slice(1)
.filter(Boolean)
.join(' - ');
console.log(result);
}