[R] Error: invalid type(list) for variable when using lm()

Fri Nov 25 19:10:59 CET 2011

On Nov 25, 2011, at 11:41 AM, Dhaynes wrote:

> Ok let me clarify
>
> I have multidimensional array and I need to convert it to a singular
> dimensional array.
> The multidimensional array is 359 rows, 2 cols, 3 deep
> I need to run a regression model mymatrix[1,1,1:3] and mymatrix  
> [1,2,1:3]
>
> This is my current error, which indicates I have the incorrect list  
> type (I
> have tried functions as.list, as.vector, as.vector)
>
> lm(formula = mymatrix[1,1,1:3]~mymatrix[1,2,1:3] )
> Error in model.frame.default(formula = mymatrix[1, 1, 1:3] ~  
> mymatrix[1,  :
>  invalid type (list) for variable 'mymatrix[1, 1, 1:3]'
>
>
> I was unsuccessful at attempting the "str(mymatrix[1,1,1:3]" -- 
> Argument not
> valid model
>
> The data.frame function did not create the objects
> <- data.frame(a=mymatrix[1,1,1:3], b=mymatrix[1,2,1:3])
>> lm(a~b, data=df)
> Error in eval(expr, envir, enclos) : object 'a' not found
>
> Here is my code
> con <- dbConnect(PostgreSQL(), user="postgres",
> password="antione",dbname="Education")
> rs <- dbGetQuery(con, "SELECT (GRADE1[10]) As grade1_t1,  
> (GRADE1[11]) As
> grade1_t2, (GRADE1[12]) As grade1_t3, (GRADE2[11]) As grade2_t2,
> (GRADE2[12]) As grade2_t3, (GRADE2[13]) As grade2_t4 FROM attending")
> myval <- rs
> attach(myval)

Generally a bad idea to attach objects. It's a sin that is committed  
by several authors but it generally gets in the way of safe code  
writing. Better to use with().

> names(myval)
> dim(myval)
>
> mymatrix <- array(myval, c(379,2,3))
>
> mymatrix[,1,1] <- grade1_t1
> mymatrix[,1,2] <- grade1_t2
> mymatrix[,1,3] <- grade1_t3
> mymatrix[,2,1] <- grade2_t2
> mymatrix[,2,2] <- grade2_t3
> mymatrix[,2,3] <- grade2_t4

But what are these various grade-named objects? Are you sure you  
didn't coerce the matrix to character mode? What is str(mymatrix)  
after this?

-- 
David.
>
> I can do this
> plot(mymatrix[1,1,1:3],mymatrix[1,2,1:3])
>
> On Fri, Nov 25, 2011 at 6:06 AM, Bert Gunter [via R] <
> ml-node+s789695n4107159h96 at n4.nabble.com> wrote:
>
>> Inline below.
>>
>> -- Bert
>>
>> On Fri, Nov 25, 2011 at 2:31 AM, Milan Bouchet-Valat <[hidden  
>> email]<http://user/SendEmail.jtp?type=node&node=4107159&i=0>>
>> wrote:
>>
>>> Le vendredi 25 novembre 2011 à 00:02 -0800, Dhaynes a écrit :
>>>> Hello,
>>>>
>>>> I am new to R.
>>>> I have multidimensional array (379,2,3) and I need to create a  
>>>> series
>> of
>>>> linear regressions (379 to be exact)
>>>> I have the array stored properly I believe, but I can not use the
>>>> lm(myarray[1,1,1:3]~myarray[1,2,1:3])
>>>> I have checked to make sure they are exactly the same length.
>>>> I have also tried endlessly to convert the subset of the array back
>> into a
>>>> vector.
>>
>> ?as.vector
>> Actually an array **is** a vector -- but with an additional "dim"
>> attribute. Try:
>>> str(x)
>>
>>
>>>>
>>>> any help would be appreciated.
>>
>> 1) Read relevant portions of R docs, like ?array and perhaps "An
>> Introduction to R."
>>
>> 2)  Read and follow the posting guide. In particular, give us a toy
>> example with the code you used to construct your array. It's  
>> difficult
>> to diagnose the source of engine failure without the car.
>>
>> 3) See my comment below.
>>
>>> The 'formula' argument of lm doesn't take actual values, but  
>>> variable
>>> names. So you need to create vectors containing your data, or pass a
>>
>> --This is patently false. Please check before giving obviously wrong
>> advice:
>>
>>> x <- array(rnorm(150), dim= c(10,5,3))
>>> lm(x[,3,2] ~x[,1,1])
>>
>> Call:
>> lm(formula = x[, 3, 2] ~ x[, 1, 1])
>>
>> Coefficients:
>> (Intercept)    x[, 1, 1]
>>    -0.1247       0.1171
>>
>>
>>
>>
>>
>>> data frame with these vectors are columns. So, going the latter  
>>> way :
>>> df <- data.frame(a=myarray[1,1,1:3], b=myarray[1,2,1:3])
>>> lm(a ~ b, data=df)
>>>
>>> or in one step
>>> lm(a ~ b, data=data.frame(a=myarray[1,1,1:3], b=myarray[1,2,1:3]))
>>>
>>>
>>> Regards
>>>
>>> ______________________________________________
>>> [hidden email] <http://user/SendEmail.jtp? 
>>> type=node&node=4107159&i=1>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.
>>>
>>
>>
>>
>> --
>>
>> Bert Gunter
>> Genentech Nonclinical Biostatistics
>>
>> Internal Contact Info:
>> Phone: 467-7374
>> Website:
>>
>> http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
>>
>> ______________________________________________
>> [hidden email] <http://user/SendEmail.jtp? 
>> type=node&node=4107159&i=2>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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David Winsemius, MD
West Hartford, CT