[R] Change data frame column names

[Don MacQueen]

Try

names(df) <- as.vector(unlist(coltitles))

This will fail if you have more than one row in your data frame coltitles.

Which is why Duncan Murdoch's second email has a better solution.

Given the difficulty in getting the titles out of the data frame in 
vector form, I would wonder why you're storing them as data in a data 
frame in the first place.

Note also that the default behavior when creating a dataframe is for 
character data to be converted to factors. You can see this with

>  class(coltitles$v1)
[1] "factor"

That's part of what gave you weird results. So I would suggest 
looking at the help pages to figure out how to prevent conversion to 
factor.

If you want names(df) to return "col number one" etc, then you have 
to create a data frame whose column names are those. You created a 
dataframe (coltitles) whose names were "v1", "v2", etc.

For example,

>  tmp <- data.frame("col number one"=1, "col number 
>two"='foobar',check.names=FALSE)
>  names(tmp)
[1] "col number one" "col number two"

But simpler and easier to just do as Duncan suggested, and create a 
vector of names.

-Don

At 2:35 PM +0000 7/15/09, 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"
>
>
>
>##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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-- 
--------------------------------------
Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA
925-423-1062