'#i#'), then the results are as you'd expect (isDefined being about 33%
slower). It seems that isDefined is doing some sort of caching to speed it
up on repetitious lookups.
Cheers,
barneyb
> -----Original Message-----
> From: Spike [mailto:[EMAIL PROTECTED]
> Sent: Monday, July 12, 2004 4:13 PM
> To: CF-Talk
> Subject: RE: StructKeyExists() vs IsDefined()
>
> Well now,
>
> This is most odd...
>
> Using the very unscientific method below it looks like isDefined() is
> actually faster than structKeyExists() at least half the
> time, or if there
> is any difference between them it is far outweighed by other
> considerations.
>
>
> <cfset time = getTickCount()>
> <cfloop from="1" to="10000" index="i">
> <cfset structKeyExists(variables,'varname1') />
> </cfloop>
>
> <cfoutput>structKeyExists(): #getTickCount() - time# <br /></cfoutput>
>
> <cfset time = getTickCount()>
>
> <cfset time = getTickCount()>
> <cfloop from="1" to="10000" index="i">
> <cfset isDefined('variables.varname2') />
> </cfloop>
>
> <cfoutput>isDefined(): #getTickCount() - time# <br /></cfoutput>
>
> This is not at all what I would have expected given that the variable
> doesn't exist in either case and that isDefined() is
> supposedly doing a
> lookup of every scope.
>
> Spike
>
> --------------------------------------------
> Stephen Milligan
> Code poet for hire
> http://www.spike.org.uk
>
> Do you cfeclipse? http://cfeclipse.tigris.org
>
>
>
>
> >-----Original Message-----
> >From: [EMAIL PROTECTED]
> >[mailto:[EMAIL PROTECTED] On Behalf Of Barney Boisvert
> >Sent: Monday, July 12, 2004 3:01 PM
> >To: CF-Talk
> >Subject: RE: StructKeyExists() vs IsDefined()
> >
> >That "glitch" is only relevant if you specify a scope name for
> >the first
> >argument of structKeyExists. So the functional difference
> will only be
> >there if you name a structure with a scope name. The fact
> >that the var is
> >empty is only because that's what I assigned it to
> initially. You can
> >change it to something else and the functionality won't change.
> >
> >The point I was making was simply that isDefined does a lot
> >more work, even
> >for seemingly simple lookups.
> >
> >Cheers,
> >barneyb
> >
> >> -----Original Message-----
> >> From: Matt Robertson [mailto:[EMAIL PROTECTED]
> >> Sent: Monday, July 12, 2004 3:51 PM
> >> To: CF-Talk
> >> Subject: Re: StructKeyExists() vs IsDefined()
> >>
> >> Barney Boisvert wrote:
> >> > <cfset variables.variables.test = "" />
> >> > <cfoutput>
> >> > #isDefined("variables.test")#<br />
> >> > #structKeyExists(variables, "test")#
> >> > </cfoutput>
> >> >
> >> > isDefined() returns true, structKeyExists() returns false.
> >>
> >> So an empty value in a defined var comes up as nonexistent.
> >Yours and
> >> Sean's points are well taken insofar as the efficiency of
> one vs. the
> >> other are concerned, but this behavior is inconsistent with
> >the avowed
> >> purpose of the function.
> >>
> >> Add this to the bottom of your code:
> >>
> >> <cfdump var="#variables#" label="local scope">
> >>
> >> You'll see that the struct is there, and the key exists. Its just
> >> empty, which to me is nto the same condition as nonexistent.
> > The docs
> >> fail to mention this quirk, but they do say it is
> >"sometimes" a usable
> >> substitute for isdefined. Too bad thats where the specifics end.
> >>
> >> You would have to build an app with this difference in behavior in
> >> mind. You couldn't just substitute one for the other to
> gain a speed
> >> improvement, which is a bummer.
> >>
> >> --
> >
> >
> >
>
>
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