You need to find the last pattern match in a string, but you do not want the overhead of finding all matches in a string and having to move to the last match in the collection of matches.
Using the
RegexOptions.RightToLeft
option, the match starts
at the end of the string and proceeds toward the beginning. The first
found match is the last match in the string. You supply the
RegexOptions.RightToLeft
constant as an argument
to the Match
method. The instance
Match
method can be used as follows:
Regex RE = new Regex(Pattern
, RegexOptions.RightToLeft); Match theMatch = RE.Match(Source
);
or use the static Regex.Match
method:
Match theMatch = Regex.Match(Source
,Pattern
, RegexOptions.RightToLeft);
where Pattern
is the regular expression
pattern and Source
is the string against
which to run the pattern.
The RegexOptions.RightToLeft
regular expression
option will force the regular expression engine to start searching
for a pattern starting with the end of the string and proceeding
backward toward the beginning of the string. The first match
encountered will be the match closest to the end of the
string—in other words, the last match in the string.