Variables in lists

[Leisha Wharfield]

Yes, but this is a way more useful explanation than what you get from 
E-Basic help, which is as dry and difficult to traverse as Death Valley.

Your solution is smarter & more economical than mine, too. I suggested 
adding an attribute to a list to get it recognized, then updating it 
with an inline object.

Thanks for the Context lesson.

Leisha

Tony Zuccolotto wrote:

>Robert,
>
>You're very close to what you need to do.   You do need to use an
>attribute in the time limit box, but the part you're missing is that all
>attributes exist in the experimental "context" and you need to get the
>value you want to use into the context.   The Context is a concept
>unique to E-Prime and it constitutes a hierarchical/multi-leveled data
>space which is separate from E-Basic variables (e.g. variables you would
>declare with the Dim statement).  The Context in E-Prime conceptually
>represents all the "experimental data" that you care about and directly
>dictates what gets written to the data file.
>
>All attributes declared on List objects automatically get put into the
>context when the List is run.   Also, stimulus presentation objects will
>insert items into the context after they run or at the end of
>procedures, e.g. to add in dependent measures like Stimulus.RT,
>Stimulus.ACC, etc.
>
>You are free to put essentially any piece of useful data into context
>via script and can do so with the following syntax.
>
>	c.SetAttrib "attributeName", value
>
>for example...
>
>Dim Dura As Long		' declare a variable in E-Basic for
>computations
>Dura = AveRT - 0.5*stddev	' do the computation
>c.SetAttrib "Dura", Dura	' add the value of the computation into
>the context under the specified name (the names used do not have to
>match).
>
>After you call c.SetAttrib and add something into the context then the
>"[Dura]" syntax can be used on object properties and at runtime the
>system will look up the value of the specified attribute.
>
>When c.SetAttrib is called and an attribute already exists then the
>attributes value will just be updated.   If the attribute doesn't
>already exist it will be created.   Every new attribute you put in the
>context it will automatically become a new column of data in the data
>file.
>
>If you need to get a value from the context via script the syntax is
>	value = c.GetAttrib( "attributeName" )
>
>When you call c.GetAttrib the system will check the current level first
>(e.g. Trial level) and if it can't resolve the reference it will move up
>the next level of the hierarchy (e.g. Block level, then Session level)
>until it finds the attribute.  If an attribute can't be found you will
>receive a runtime error.  
>
>For more information you should look in the E-Basic help system under
>the Context object.
>
>Hope that helps.
>-Tony
>
>Anthony P. Zuccolotto
>President and Chief Executive Officer
>Psychology Software Tools, Inc.
>2050 Ardmore Boulevard
>Suite 200
>Pittsburgh, PA 15221-4610
>Phone     412-271-5040
>FAX       412-271-7077
>Email     anthony.zuccolotto at pstnet.com
>Internet  http://www.pstnet.com
>
>
>  
>
>>-----Original Message-----
>>From: eprime at mail.talkbank.org [mailto:eprime at mail.talkbank.org] On
>>    
>>
>Behalf
>  
>
>>Of Robert F. Buzan
>>Sent: Tuesday, March 21, 2006 12:48 PM
>>To: eprime at mail.talkbank.org
>>Subject: Variables in lists
>>
>>I'm a fairly green E-Prime programmer and have encountered a problem I
>>can't
>>find an answer for.  I'd appreciate any help that anyone can provide.
>>    
>>
>I'm
>  
>
>>trying to create an experiment that limits the amount of time that
>>participants can respond.  It's done in this way:
>>
>>RT data is collected in the practice phase and the mean and standard
>>deviation
>>are computed.  We then create a variable to be used for the allowable
>>response
>>duration on one of the later blocks, thusly:  Dura = AveRT -
>>    
>>
>0.5*stddev.
>  
>
>>This
>>works just fine.
>>
>>Later, when I need to use this, I want to set the allowable response
>>    
>>
>time
>  
>
>>for
>>the stimulus to which participants must respond to Dura.  We've tried
>>putting
>>Dura directly into the timelimit box, but it must be an integer or an
>>attribute.  We've tried putting [Dura] directly into the timelimit
>>    
>>
>box,
>  
>
>>but
>>that is considered an attribute.  We've created a separate attribute,
>>[MyTime], and populated that column with Dura (which, I believe, it
>>interprets
>>as a string) or with [Dura] (which is then an attribute).  I think
>>    
>>
>I've
>  
>
>>narrowed the problem down to this question:  How do I use a variable
>>    
>>
>in a
>  
>
>>list?
>>
>>If that's the wrong question, does anyone have a suggestion for making
>>this
>>program limit response time to the value of Dura (Average RT minus
>>    
>>
>one-
>  
>
>>half
>>the standard deviation)?
>>
>>Thanks for your help.
>>
>>Gratefully,
>>
>>Robb Buzan
>>
>>    
>>
>
>
>
>  
>
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