Forgot one thing, make sure your data is a list or data frame.
On Tue, May 12, 2009 at 12:19 PM, Jun Shen <jun.shen...@gmail.com> wrote:
> I don't think get(factor[i]) will work. The problem is get only sees a
> character string "data$focus" instead of doing "extracting focus from data".
> In your case isn't lapply (or sapply) good enough?
>
> sapply (data, summary)
>
> try ?lapply for details
>
> Jun
>
> On Tue, May 12, 2009 at 10:55 AM, rapton <mattc...@gmail.com> wrote:
>
>>
>> Hello,
>>
>> I have a data set with many variables, and often I want to run a given
>> function, like summary() or cor() or lmer() etc. on many combinations of
>> one
>> or more than one of these variables. For every combination of variables I
>> want to analyze I have been writing out the code by hand, but given that I
>> want to run many different functions over dozens and dozens of variables
>> combinations it is taking a lot of time and making for very inelegent
>> code.
>> There *has* to be a better way! I have tried looking through numerous
>> message boards but everything I've tried has failed.
>>
>> It seems like loops would solve this problem nicely.
>> (1) Create list of variables of interest
>> (2) Iterate through the list, running a given function on each variable
>>
>> I have a data matrix which I have creatively called "data". It has
>> variables named "focus" and "productive".
>>
>> If I run the function summary(), for instance, it works fine:
>> summary(data$focus)
>> summary(data$productive)
>>
>> Both of these work.
>>
>> If I try to use a loop like:
>>
>> factors <- c("data$focus", "data$productive")
>> for(i in 1:2){
>> summary(get(factors[i]))
>> }
>>
>> It given the following errors:
>> Error in get(factors[i]) : variable "data$focus" was not found
>> Error in summary(get(factors[i])) :
>> error in evaluating the argument 'object' in selecting a method for
>> function 'summary'
>>
>> But data$focus *does* exist! I could run summary(data$focus) and it works
>> perfectly.
>>
>> What am I doing wrong?
>>
>> Even if I get this working, is there a better way to do this, especially
>> if
>> I have dozens of variables to analyze?
>>
>> Any ideas would be greatly appreciated!
>> --
>> View this message in context:
>> http://www.nabble.com/Using-loops-to-run-functions-over-a-list-of-variables-tp23505399p23505399.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
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>>
>
>
>
> --
> Jun Shen PhD
> PK/PD Scientist
> BioPharma Services
> Millipore Corporation
> 15 Research Park Dr.
> St Charles, MO 63304
> Direct: 636-720-1589
>
>
--
Jun Shen PhD
PK/PD Scientist
BioPharma Services
Millipore Corporation
15 Research Park Dr.
St Charles, MO 63304
Direct: 636-720-1589
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