[R] Error in rowMeans function

[yrosseel]

On 10/15/2012 08:28 AM, PIKAL Petr wrote:
> Hi
>
>
>> -----Original Message----- From: r-help-bounces at r-project.org
>> [mailto:r-help-bounces at r- project.org] On Behalf Of Gunsalus,
>> Catherine Sent: Friday, October 12, 2012 8:52 PM To:
>> r-help at r-project.org Subject: [R] Error in rowMeans function
>>
>> Hello, I am trying to create parcels for a CFA model.  I am trying
>> to average 6 sets of 3 variables each into parcels.  I don't
>> understand why I am getting an error message as follows: Thanks for
>> your help, Catherine
>>
>>
>>
>> atds1par <- rowMeans(semHW1dat1[, c("atds1", "atds2", "atds3")],
>> na.rm=TRUE)
>>
>> atds2par <- rowMeans(semHW1dat1[, c("atds4", "atds5", "atds6")],
>> na.rm=TRUE)
>>
>> atds3par <- rowMeans(semHW1dat1[, c("atds7", "atds8", "atds9")],
>> na.rm=TRUE)
>>
>>
>>
>> sgs1par <- rowMeans(semHW1dat1[, c("sgs1", "sgs2", "sgs3")],
>> na.rm=TRUE)
>>
>> sgs2par <- rowMeans(semHW1dat1[, c("sgs4", "sgs5", "sgs6")],
>> na.rm=TRUE)
>>
>> sgs3par <- rowMeans(semHW1dat1[, c("sgs7", "sgs8", "sgs9")],
>> na.rm=TRUE)

The cfa() function requires that all variables that are specified in the 
model syntax are included in a data.frame. So after constructing  your 
parcels, you need to create a new data.frame containing them:

Data <- data.frame(ads1par=atds1par, atds2par=atds2par, 
atds3par=atds3par, sgs1par=sgs1par, sgs2par=sgs2par, sgs3par=sgs3par)

then, you can call the cfa() function but with 'Data' as your data 
argument (note: no need to provide sample.nobs, we get it from the 
data.frame):

parout1 <- cfa(parmod1, data=Data, std.lv=TRUE)

Hope this helps,

Yves
http://lavaan.org