renaming column names

Dear David

Problem solved ! Remarkably, I saw your previous post about stringsasFactors
<- false and that was the root of the problem. I was trying to rename the
columns according to contents of one of the rows of the data frame, which
were being interpreted as factors (which I hadn't realised) and that's why
the assignment as new column names didn't work !

Thanks for your help, albeit inadvertent !

Benny



Benjamin Chain
Division of Infection and Immunity
Windeyer Building
UCL, 46 Cleveland St.
London W1T 4JF
Fax 00 44 20 7679 9301


-----Original Message-----
From: David Winsemius [mailto:dwinsemius at comcast.net] 
Sent: 31 May 2009 17:11
To: Benny Chain
Cc: r-help at r-project.org
Subject: Re: [R] renaming column names

Cannot reproduce with a toy example:

 > data <- data.frame(a=1:3, b=4:6, c=6:8)
 > colnames(data) <- c("d","e","f")
 > colnames(data)
[1] "d" "e" "f"


Perhaps you need to produce more detail. Surely offering the results  
of dput(a) would not tax the limits of the R-mail server.

David

On May 31, 2009, at 11:58 AM, Benny Chain wrote:

> I am trying to rename the column names of a data frame called  
> "data". It has
> 177 columns. I have used :
>
> colnames(data) <- a
>
>
>
> where a is a vector with 177 character names.
>
>
>
> I don't get any error message, but the column names don't change  
> because
> when I then type :
>
> colnames(data)
>
>
>
> I get the same set of names as before, so the assignment doesnt seem  
> to have
> worked.
>
>
>
> Any ideas or suggestions gratefully received.
>
>
>
> Benny Chain
>
> Benjamin Chain
>
> Division of Infection and Immunity
>
> Windeyer Building
>
> UCL, 46 Cleveland St.
>
> London W1T 4JF
>
> Fax 00 44 20 7679 9301
>
>
>
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
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> PLEASE do read the posting guide
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> and provide commented, minimal, self-contained, reproducible code.

David Winsemius, MD
Heritage Laboratories
West Hartford, CT