[Mono-list] String comparisons slow

[Bojan Rajkovic]

Hi Alexander,

My understanding based on the documentation is that StringComparison.Ordinal
is essentially a C strcmp (in fact, it may be implemented as such under the
hood, via an icall to the C runtime code), and StringComparison.Invariant is
aware of surrogate pairs and composed characters, and is a linguistic
comparison (ie. this *letter* comes before the other, not this character
code).

--Bojan

2010/7/22 Alexander M. Batishchev <abatishchev at godfather.net.ru>

> Michael, could you please clarify the difference between Ordinal and
> Invariant string comparison?
>
> -----Original Message-----
> From: mono-list-bounces at lists.ximian.com
> [mailto:mono-list-bounces at lists.ximian.com] On Behalf Of Michael
> Hutchinson
> Sent: Thursday, July 22, 2010 12:29 AM
> To: David S
> Cc: mono-list at lists.ximian.com; wtftc
> Subject: Re: [Mono-list] String comparisons slow
>
> On Wed, Jul 21, 2010 at 3:30 PM, David S <buttink at gmail.com> 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.
>
> --
> Michael Hutchinson
> http://mjhutchinson.com
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