Group 1(Jan(uary)?|Feb(ruary)?|Mar(ch)?|Apr(il)?|May|Jun(e)?|Jul(y)?|Aug(ust)?|Sep(tember)?|Oct(ober)?|Nov(ember)?|Dec(ember)?) 1st AlternativeJan(uary)? Janthe literal text Jan (case sensitive) ?repeats the group contents below at most once:
uarythe literal text uary (case sensitive) 2nd AlternativeFeb(ruary)? Febthe literal text Feb (case sensitive) ?repeats the group contents below at most once:
ruarythe literal text ruary (case sensitive) Marthe literal text Mar (case sensitive) ?repeats the group contents below at most once:
chthe literal text ch (case sensitive) Aprthe literal text Apr (case sensitive) ?repeats the group contents below at most once:
ilthe literal text il (case sensitive) Maythe literal text May (case sensitive) Junthe literal text Jun (case sensitive) ?repeats the group contents below at most once:
ethe literal e (10110 / 1458 / 6516) (case sensitive)
Julthe literal text Jul (case sensitive) ?repeats the group contents below at most once:
ythe literal y (12110 / 1718 / 7916) (case sensitive)
Augthe literal text Aug (case sensitive) ?repeats the group contents below at most once:
ustthe literal text ust (case sensitive) 9th AlternativeSep(tember)? Septhe literal text Sep (case sensitive) ?repeats the group contents below at most once:
temberthe literal text tember (case sensitive) 10th AlternativeOct(ober)? Octthe literal text Oct (case sensitive) ?repeats the group contents below at most once:
oberthe literal text ober (case sensitive) 11th AlternativeNov(ember)? Novthe literal text Nov (case sensitive) ?repeats the group contents below at most once:
emberthe literal text ember (case sensitive) 12th AlternativeDec(ember)? Decthe literal text Dec (case sensitive) ?repeats the group contents below at most once:
emberthe literal text ember (case sensitive) \s+a Unicode whitespace character, repeated at least once
\d{1,2}a Unicode decimal digit, repeated between 1 and 2 times
,the literal , (4410 / 548 / 2C16)
\s+a Unicode whitespace character, repeated at least once
\d{4}a Unicode decimal digit, repeated exactly 4 times
g modifier: global. Finds all matches instead of stopping after the first
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string