... and wrap it all up into a single function call that could even
have the user interactively supply the input data file names.
Cheers,
Bert
Bert Gunter
Genentech Nonclinical Biostatistics
(650) 467-7374
"Data is not information. Information is not knowledge. And knowledge
is certainly not wisdom."
Clifford Stoll
On Wed, Jun 25, 2014 at 8:23 AM, Jeff Newmiller
<jdnew...@dcn.davis.ca.us> wrote:
> Seems to me you are creating your own troubles in your "requirements". If the
> analysis is the same from case to case, it makes more sense to use a single
> set of object names within the analysis and change only the names of the
> input and output files.
> ---------------------------------------------------------------------------
> Jeff Newmiller The ..... ..... Go Live...
> DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go...
> Live: OO#.. Dead: OO#.. Playing
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> ---------------------------------------------------------------------------
> Sent from my phone. Please excuse my brevity.
>
> On June 25, 2014 7:53:33 AM PDT, David Stevens <david.stev...@usu.edu> wrote:
>>Greg - I appreciate your taking the time to explain. This is very
>>helpful. My case was a bit unusual as I'm helping a colleague with code
>>
>>to use on a regular but individual basis. I want them to name a data
>>set
>>once at the top of the script and have that name propagate through
>>several objects that end up being saved at the end with file names tied
>>
>>to the data set name. Then tomorrow, they'll do the same thing on a
>>different data set so each session would be pretty simple, with only
>>2-3
>>named objects at the end, though the data sets are big and cumbersome.
>>
>>I'll dig into this more and apologize to those who thought this problem
>>
>>was too trivial for the r-help forum.
>>
>>David
>>
>>On 6/24/2014 4:00 PM, Greg Snow wrote:
>>> The main reason to avoid assign/get is that there are better ways.
>>> You can use a list or environment more directly without using
>>> assign/get. Also the main reason to use assign/get is to work with
>>> global variables which are frowned on in general programming (and
>>> prone to hard to find bugs).
>>>
>>> Consider the following code snippet:
>>>
>>> x <- 1:10
>>> functionThatUsesAssign(x)
>>>
>>> what is the value of x after running this code? If you use global
>>> variables then the answer is "I don't know", and if x was something
>>> that took several hours to compute and I just accidentally overwrote
>>> it, then I am probably not happy.
>>>
>>> Using assign often leads to the temptation to try code like:
>>>
>>> assign( "x[5]", 25 )
>>>
>>> which does something (no warnings, no errors) but generally not what
>>> was being attempted.
>>>
>>> Another common (mis)use of assign/get is to create a sequence of
>>> variables like "data01", "data02", "data03", ... and then do the
>>same
>>> thing for each of the data objects. This is much better done by
>>> putting all the objects into a single list, then you can easily
>>> iterate over the list using lapply/sapply or still access the
>>> individual pieces. Then when it comes time to save these objects,
>>you
>>> only need to save the list, not all the individual objects, same for
>>> deleting, copying, moving, etc. And you don't have a bunch of
>>> different objects cluttering your workspace, just a single list.
>>>
>>> On Tue, Jun 24, 2014 at 2:57 PM, David Stevens
>><david.stev...@usu.edu> wrote:
>>>> Thanks to all for the replies. I tried all three and they work
>>great. I was
>>>> misinterpreting the list = parameter in save(...) and I get your
>>point about
>>>> overwriting existing objects. I've heard about not using assign/get
>>before.
>>>> Can anyone point me to why and what alternatives there are?
>>>>
>>>> Regards
>>>>
>>>> David
>>>>
>>>>
>>>> On 6/24/2014 2:50 PM, Henrik Bengtsson wrote:
>>>>> I recommend to use saveRDS()/readRDS() instead. More convenient
>>and
>>>>> avoids the risk that load() has of overwriting existing variables
>>with
>>>>> the same name.
>>>>>
>>>>> /Henrik
>>>>>
>>>>> On Tue, Jun 24, 2014 at 1:45 PM, Greg Snow <538...@gmail.com>
>>wrote:
>>>>>> I think that you are looking for the `list` argument in `save`.
>>>>>>
>>>>>> save( list=foo, file=paste0(foo, '.Rdata') )
>>>>>>
>>>>>> In general it is best to avoid using the assign function (and get
>>when
>>>>>> possible). Usually there are better alternatives.
>>>>>>
>>>>>> On Tue, Jun 24, 2014 at 2:35 PM, David Stevens
>><david.stev...@usu.edu>
>>>>>> wrote:
>>>>>>> R community,
>>>>>>>
>>>>>>> Apologies if this has been answered. The concept I'm looking for
>>is to
>>>>>>> save() an object retrieved using get() for an object
>>>>>>> that resulted from using assign. Something like
>>>>>>>
>>>>>>> save(get(foo),file=paste(foo,'rData',sep=''))
>>>>>>>
>>>>>>> where assign(foo,obj) creates an object named foo with the
>>contents of
>>>>>>> obj
>>>>>>> assigned. For example, if
>>>>>>>
>>>>>>> x <- data.frame(v1=c(1,2,3,4),v2=c('1','2','3','4'))
>>>>>>> foo = 'my.x'
>>>>>>> assign(foo,x)
>>>>>>> # (... then modify foo as needed)
>>>>>>> save(get(foo),file=paste(foo,'.rData',sep=''))
>>>>>>>
>>>>>>> # though this generates " in save(get(foo), file = paste(foo,
>>".rData",
>>>>>>> sep
>>>>>>> = "")) :
>>>>>>> object ‘get(foo)’ not found", whereas
>>>>>>>
>>>>>>> get(foo)
>>>>>>>
>>>>>>> at the command prompt yields the contents of my.x
>>>>>>>
>>>>>>> There's a concept I'm missing here. Can anyone help?
>>>>>>>
>>>>>>> Regards
>>>>>>>
>>>>>>> David Stevens
>>>>>>>
>>>>>>> --
>>>>>>> David K Stevens, P.E., Ph.D.
>>>>>>> Professor and Head, Environmental Engineering
>>>>>>> Civil and Environmental Engineering
>>>>>>> Utah Water Research Laboratory
>>>>>>> 8200 Old Main Hill
>>>>>>> Logan, UT 84322-8200
>>>>>>> 435 797 3229 - voice
>>>>>>> 435 797 1363 - fax
>>>>>>> david.stev...@usu.edu
>>>>>>>
>>>>>>> ______________________________________________
>>>>>>> R-help@r-project.org mailing list
>>>>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>>>>> PLEASE do read the posting guide
>>>>>>> http://www.R-project.org/posting-guide.html
>>>>>>> and provide commented, minimal, self-contained, reproducible
>>code.
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Gregory (Greg) L. Snow Ph.D.
>>>>>> 538...@gmail.com
>>>>>>
>>>>>> ______________________________________________
>>>>>> R-help@r-project.org mailing list
>>>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>>>> PLEASE do read the posting guide
>>>>>> http://www.R-project.org/posting-guide.html
>>>>>> and provide commented, minimal, self-contained, reproducible code.
>>>>
>>>> --
>>>> David K Stevens, P.E., Ph.D.
>>>> Professor and Head, Environmental Engineering
>>>> Civil and Environmental Engineering
>>>> Utah Water Research Laboratory
>>>> 8200 Old Main Hill
>>>> Logan, UT 84322-8200
>>>> 435 797 3229 - voice
>>>> 435 797 1363 - fax
>>>> david.stev...@usu.edu
>>>>
>>>> ______________________________________________
>>>> R-help@r-project.org mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>> PLEASE do read the posting guide
>>http://www.R-project.org/posting-guide.html
>>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>>
>>
>>--
>>David K Stevens, P.E., Ph.D.
>>Professor and Head, Environmental Engineering
>>Civil and Environmental Engineering
>>Utah Water Research Laboratory
>>8200 Old Main Hill
>>Logan, UT 84322-8200
>>435 797 3229 - voice
>>435 797 1363 - fax
>>david.stev...@usu.edu
>>
>>______________________________________________
>>R-help@r-project.org mailing list
>>https://stat.ethz.ch/mailman/listinfo/r-help
>>PLEASE do read the posting guide
>>http://www.R-project.org/posting-guide.html
>>and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
______________________________________________
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