[R] passing a variable (containing the value of the argument) to a function

[Spencer Graves]

Hi, Peter:  I'll have to study your example and alternatives.  spencer 
graves

Peter Dalgaard wrote:

>Spencer Graves <spencer.graves at pdf.com> writes:
>
>  
>
>>Hi, Peter:     How does that compare with the following: for (myname
>>in names(myframe)[1:4]){
>>  mdl <- formula(paste(myname, "~ etc.etc"))
>>  myfit <- lm(mdl, data=myframe)
>>  print(summary(myfit))
>>}
>>
>>      Or: for (myname in names(myframe)[1:4]){
>>  lm.txt <- paste("lm(", myname, "~ etc.etc, data=myframe)")
>>   myfit <- eval(parse(text=lm.txt))
>>  print(summary(myfit))
>>}
>>
>>      You are teaching me new uses of "substitute", and I just wonder
>>about the relative advantages and disadvantages of the different
>>approaches.     Thanks,
>>      spencer graves
>>    
>>
>
>Those variants should work (and similar code is all over the place in
>the modelling functions). I just tend to prefer to avoid going via the
>textual representation. There are a couple of devils lurking in there,
>in particular if a data frame has variables with "funny names" -
>spaces or special characters inside, for example.
>
>To wit:
>
>  
>
>>myname <- "foo bar"
>>lm.txt <- paste("lm(", myname, "~ etc.etc, data=myframe)")
>>lm.txt
>>    
>>
>[1] "lm( foo bar ~ etc.etc, data=myframe)"
>  
>
>>parse(text=lm.txt)
>>    
>>
>Error in parse(file, n, text, prompt) : parse error
>
>
>  
>