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如何使用javascript regexp捕获特定组?

regex javascript

Andrew Li · 技术社区 · 6 年前

给定从PDF中提取的示例文本:

Professional Learning - August 31  Labor Day - September 3 Intersession- October 19 Professional Learning - October 22 Thanksgiving Break - November 21-23 Winter Break - December 24 - January 4 Martin Luther King, Jr. Day - January 21 Presidentsâ Day - February 18 Spring Break - March 18-22 Teacher Comp Day - April 19

我的目标是捕获所有的月和日,即它应该捕获以下所有内容:

August 31
October 19
March 18-22
December 24 - January 4
December 24-January 4

困难的部分是捕捉月份不一样的范围。我想出了这个规则:

/(January|February|March|April|May|August|September|October|November|December)\\s([0-9]*-?[0-9]+)(\s*-\s*(January|February|March|April|May|August|September|October|November|December)\\s([0-9]*-?[0-9]+))?/g

除了上面列出的最后两个例子之外,它对所有人都很有用。打开 regexr ,它显示它在捕获组3中捕获它很好,但我不能在javascript中访问它。以这个片段为例:

const string = 'Professional Learning - August 31  Labor Day - September 3 Intersession- October 19 Professional Learning - October 22 Thanksgiving Break - November 21-23 Winter Break - December 24 - January 4 Martin Luther King, Jr. Day - January 21 Presidentsâ Day - February 18 Spring Break - March 18-22 Teacher Comp Day - April 19';

const subRegex = '(January|February|March|April|May|August|September|October|November|December)\\s([0-9]*-?[0-9]+)';
const dateRegex = new RegExp(`${subRegex}(\s*-\s*${subRegex})?`, 'g');

console.log(string.match(dateRegex));

好像我能抓到 December 24 和 January 4 分开,但不在一起。有没有办法把他们抓在一起?

1 回复 | 直到 6 年前

CertainPerformance 6 年前

你只需要调整(也许简化)你原来的RE一点:

const str = 'Professional Learning - August 31  Labor Day - September 3 Intersession- October 19 Professional Learning - October 22 Thanksgiving Break - November 21-23 Winter Break - December 24 - January 4 Martin Luther King, Jr. Day - January 21 Presidentsâ Day - February 18 Spring Break - March 18-22 Teacher Comp Day - April 19';
// str2 has "December 24-January 4" instead - no spaces
const str2 = 'Professional Learning - August 31  Labor Day - September 3 Intersession- October 19 Professional Learning - October 22 Thanksgiving Break - November 21-23 Winter Break - December 24-January 4 Martin Luther King, Jr. Day - January 21 Presidentsâ Day - February 18 Spring Break - March 18-22 Teacher Comp Day - April 19';
const re = /(January|February|March|April|May|August|September|October|November|December) [\d-]+([ -]*(January|February|March|April|May|August|September|October|November|December) \d+)?/g;
console.log(str.match(re));
console.log(str2.match(re));