\ba Unicode word boundary
Non-Capturing Group(?:de las|entre las|desde las|y las|a las|las|de|a) de lasthe literal text de las (case sensitive) entre lasthe literal text entre las (case sensitive) desde lasthe literal text desde las (case sensitive) y lasthe literal text y las (case sensitive) a lasthe literal text a las (case sensitive) lasthe literal text las (case sensitive) dethe literal text de (case sensitive) athe literal a (9710 / 1418 / 6116) (case sensitive)
\s+a Unicode whitespace character, repeated at least once
\d+a Unicode decimal digit, repeated at least once
Non-Capturing Group(?:\s+\d+)? ?repeats the group contents below at most once:
\s+a Unicode whitespace character, repeated at least once
\d+a Unicode decimal digit, repeated at least once
\s*a Unicode whitespace character, repeated any number of times
Non-Capturing Group(?:pm|am|de la tarde)? ?repeats the group contents below at most once:
pmthe literal text pm (case sensitive) amthe literal text am (case sensitive) 3rd Alternativede la tarde de la tardethe literal text de la tarde (case sensitive) 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