Regex Tester & Validator

Matches a period followed by a space only when it is NOT a decimal point between digits (e.g., it skips the dot in '3.14 '). It uses a negative lookbehind containing an embedded lookahead—a PCRE2 feature—to verify the preceding character isn't a digit that continues into a fractional number. Useful for finding sentence-ending punctuation in text that also contains decimal numbers.