Javascript反向引用后跟数字 [英] Javascript backreference followed by number

问题描述

如果我有一个正则表达式，例如13个捕获组，我如何指定包含第一个反向引用后跟文字3的替换字符串？

If I had a regular expression with, say 13 capturing groups, how would I specify a replacement string that contained the first backreference followed by the literal '3'?

var regex = /(one)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)/;
"one2345678910111213".replace(regex,"$13");
//Returns "13". How do I return "one3"?

我能找到的最接近的问题是这一个，但它与perl有关，并且不包括硬编码的文字。

The closest question I could find was this one, but it pertains to perl and did not include a hardcoded literal.

还看了 docs ，但没有明确说明或在示例中演示。

Also had a look at the docs on MDN, but there was nothing explicitly stated or demonstrated in the examples.

推荐答案

好抓！我能想出的唯一解决方案是：

Good catch! The only solution I've been able to come up with is:

var regex = /(one)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)/;
"one2345678910111213".replace(regex, function(match, $1) { return $1 + "3"; } );

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编辑我看了 ECMAScript规范，看起来没有回调就可以实现。一些RegExp替换引擎 - 例如Python - 有一个 \ g 构造（对于group），你可以使用类似的东西替换字符串中的\g {1} 3 ;但JavaScript只使用 $ nn 。也就是说，如果你有超过9个捕获组，你可以使用两位数的反向引用来消除歧义，如下所示：

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EDIT I looked up the ECMAScript spec and it looks like this is possible without a callback. Some RegExp replacement engines -- Python, for example -- have a \g construct (for "group"), where you can use something like \g{1}3 in the replacement string; but JavaScript just uses $nn. That is, if you've got more than 9 capturing groups, you can use a two-digit back reference to remove the ambiguity, like so:

"one2345678910111213".replace(regex, "$013" );

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