CODEWITHSUNDEEP
javascriptregexpattern-matching
hello
hello

Reputation: 1228

regex to start with a capturing group

I have this regEx to match the following patterns:

/(((fall|spring|summer)\s\d{4});|(waived)|(sub\s[a-zA-Z]\d{3}))/ig

Should match:

fall 2000;
spring 2019; waived
summer 1982; sub T676

Should not match ANY string that does not start with the first capturing group ((fall|spring|summer)\s\d{4}) such as:

waived Fall 2014;
sub Fall 2011; waived

To make sure that each matching pattern starts with this group ((fall|spring|summer)\s\d{4}) I tried appending ^ in front of the first group like this, /(^((fall|spring|summer)\s\d{4});|(waived)|(sub\s[a-zA-Z]\d{3}))/ig, but the results were inconsistent.

Demo

Upvotes: 1

Views: 9433

Answers (1)

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626689

You may use

/^(fall|spring|summer)\s\d{4};(?:.*(waived|sub\s[a-zA-Z]\d{3}))?/i

See the regex demo.

Details

  • ^ - start of string
  • (fall|spring|summer) - one of the three alternatives
  • \s - a whitespace
  • \d{4} - 4 digits
  • ; - a semi-colon
  • (?:.*(waived|sub\s[a-zA-Z]\d{3}))? - an optional sequence of:
    • .* - any 0+ chars other than line break chars, as many as possible (if the values you need are closer to the start of string, replace with a lazy .*? counterpart)
    • ( - start of a grouping construct
      • waived - a waived substring
      • | - or
      • sub - a sub substring
      • \s - a substring
      • [a-zA-Z] - an ASCII letter
      • \d{3} - three digits
    • ) - end of the grouping construct.

Upvotes: 2

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