正则表达式忽略捕获组顺序

Question

\b(f|fall|w|winter|s|spring|su|summer)\b\s*(?<!\d)(\d{4}|\d{2})(?!\d)

Fall 2018
fall 18
2016 Fall
F2016
Fall2016

我定义的正则表达式对所有测试字符串都很好，除了当捕获组顺序被交换时（2016 Fall或16F或18SU)，正则表达式中是否有一种方法可以忽略正则表达式的捕获组顺序

Answer 1

您可以使用一个交替的两个部分，其中年份和季节是交换的，然后只抓取匹配的捕获：

\b(?:(f(?:all)?|w(?:inter)?|s(?:pring|u(?:mmer)?)?)\s*(\d{2}(?:\d{2})?)|(\d{2}(?:\d{2})?)\s*(f(?:all)?|w(?:inter)?|s(?:pring|u(?:mmer)?)?))\b

参见regex演示

我承包了您的替代方案，以使匹配更有效：所有替代方案应该只在唯一的位置匹配。对于你的情况来说，词的界限似乎已经足够了。

var strs = ['Fall 2018','fall 18','2016 Fall','F2016','Fall2016'];
var season = "(f(?:all)?|w(?:inter)?|s(?:pring|u(?:mmer)?)?)";
var year = "(\\d{2}(?:\\d{2})?)";
var p = new RegExp("\\b(?:" + season + "\\s*" + year + "|" + year + "\\s*"+ season + ")\\b","i");
var results=[], m;
for (var s of strs) {
  m  = s.match(p);
  if (m) {
    if (m[1]) {
      console.log(m[1],":", m[2]); 
    } else {
      console.log(m[3],":", m[4]); 
    }
  }
}