[R] Change data frame column names

[Duncan Murdoch]

On 7/15/2009 10:35 AM, Tom Liptrot wrote:
> 
> 
> 
> Hi R helpers,
> 
> I have a data frame and I want to change the column names to names I have held in another data frame, but I am having difficulty. All data framnes are large so i can't input manually. Below is what i have tried so far:
> 
> df<-data.frame(a=1:5, b=2:6, d=3:7, e=4:8)
> coltitles<-data.frame(v1="col number one", v2="col number two", v3="col number three", v4="col number four")
> 
> ##first attempt
> 
> names(df)<-coltitles
> names(df)
> [1] "1" "1" "1" "1"   ###not what i wanted as I want names(df) to return [1] "col number one" "col number two" "col number three" "col number four"

Not sure if my first reply went out; it had an error in it, because I 
misread what you were trying to do.

You want to assign a character vector as names.  You can set it up like 
that originally using

coltitles <- c("col number one", "col number two", "col number three", 
"col number four")

and then your first attempt will work.  If you need to get the names out 
of a dataframe, then use

names(x) <- coltitles[1,]

to select the first row (or select some other row if you want) of the 
dataframe to use as names.

Duncan Murdoch

> 
> ##second attempt
> 
> coltitles<-as.vector(coltitles, mode="character")  ##trying to convert to a character vector after looking at help
> is.vector(coltitles)
> [1] TRUE
> names(df)<-coltitles
> names(df)
> [1] "1" "1" "1" "1"   ###again not what I wanted
> 
> How can I convert the column names?
> 
> Thanks in advance,
> 
> Tom
> 
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