InDesign uses a Perl flavor of regex.1 The following are some useful expressions I have accumulated over the years.
\b(([Pp]age)|(p+\.))\s\d+This looks for contiguous white space characters and removes all but the last instance.
Find:
(\s+)(\s)Replace:
$2As far as I know this is not documented by Adobe directly. See this question on the graphic design Stack Exchange.↩︎