While jonp has already explained it though... StringComparison.Ordinal means comparison in Unicode character codepoint order. Invariant comparison is culture-aware comparison that includes "natural" sortings (i.e. sorting like A->a->B->b), processing combined characters (AE == \u00C6) etc. They are mostly common to all cultures, while there are some difference between cultures e.g. CJK ideography character sortings differ a lot among those cultures. Some Latin1 character orders differ for each European culture. For more details, see Collation-notes.txt in corlib/Mono.Globalization.Unicode: http://anonsvn.mono-project.com/viewvc/trunk/mcs/class/corlib/Mono.Globalization.Unicode/Collation-notes.txt
Atsushi Eno On 2010/07/22 14:50, Alexander M. Batishchev wrote: > Michael, could you please clarify the difference between Ordinal and > Invariant string comparison? > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Michael Hutchinson > Sent: Thursday, July 22, 2010 12:29 AM > To: David S > Cc: [email protected]; wtftc > Subject: Re: [Mono-list] String comparisons slow > > On Wed, Jul 21, 2010 at 3:30 PM, David S<[email protected]> wrote: > >> Ok. Now I'm confused. How come "CurrentCulture" for US/ENG doesn't just >> > run > >> the Ordinal??? Perhaps there are some weird alphabetizing things I just >> don't understand. BTW, Thanks for tell us about the StringComparer class. >> > I > >> never knew that existed. >> > Note also that some string methods have overloads for taking specific > cultures, or the StringComparison enum. Both StringComparison.Ordinal > and StringComparison.OrdinalIgnoreCase (as well as StringComparer) can > be very useful to improve performance when culture-dependent behaviour > is not needed or desirable. > > Culture-dependent string comparisons are a very complex topic. There's > also an "invariant" culture for doing things in a culture-independent > way. > > _______________________________________________ Mono-list maillist - [email protected] http://lists.ximian.com/mailman/listinfo/mono-list
