[R] data.frame required for cca in ade4

[Gavin Simpson]

On Sat, 2010-07-17 at 13:15 +0800, elaine kuo wrote:
> Dear List,
> 
> I tried to conduct cca using csv data but failed.
> The message said that data.frame is required.
> 
> Please kindly share how to convert a csv-imported file to a data.frame.
> Thank you.

It was a dataframe. You aren't giving ade4:::cca a dataframe because you
are extracting a single component of that data frame in your call.

Witness:

> dat <- data.frame(X = rnorm(10), Y = rnorm(10))
> class(dat$X)
[1] "numeric"
> is.data.frame(dat$X)
[1] FALSE

The reason ade4:::cca expects a dataframe is that CCA is generally used
for a *multivariate* response. Here you are supplying a univariate
response.

HTH

G

> 
> Elaine
> 
> code
> 
> rm(list=ls())
> spec <-read.csv("c:/migration/M_R_20100718_winterM_spec_vegan.csv",header=T,
> row.names=1)
> dim(spec)
> spec[1,]
> 
> envi <-read.csv("c:/migration/M_R_20100718_winterM_envi_vegan.csv",header=T,
> row.names=1)
> dim(envi)
> envi[1,]
> 
> library(ade4)
> 
> w.cca  <-  cca(spec$WinterM_ratio, envi, scan=TRUE)
> error in cca(spec$WinterM_ratio, envi, scan = FALSE) :
>   data.frame expected
> 
> 	[[alternative HTML version deleted]]
> 
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