R help - Jul 2010 - adding a row of names to data.frame

Relative noob here, I have a data.frame and simply want to add an explicit
column of names in column 1 of the form
"trial_number01" for row 1, "trial_number02" for row 2 ....
etc.  It is simply for visual purposes and to explain data to others.  I've
tried
Using row.names and other but still no luck, am sure it has been covered but I
can't find it, can you please point me in the right direction?

Thanks

Jim


==============================Dr. Jim Maas
University of East Anglia
Norwich, UK


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Jim

Is this what you need?

#create data
Lines <- "Drug1 Drug2 Drug3 Drug4
  153  133  145  111
  189  177  200  170
  221  241  187  243
  215  228  201  178
  302  283  292  248
  223  255  220  202
  201  238  233  163
  173  164  172  139
  121  128  119  120
  100  200  300  400"

# read in data
d <- read.table(textConnection(Lines), header = TRUE)

#add row.names
row.names(d)=paste("trial_number",sprintf("%02d",as.numeric(row.names(d))),sep="")

# view output
print(d)

HTH

Pete

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Thanks Pete,

It works fine.  I should have explained, already had the data.frame with
data in it, just wanted to add a string vector into the first column of the
data.frame, could not figure out how to do that.

Jim
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On Jul 6, 2010, at 8:00 AM, jamaas wrote:
>
> Thanks Pete,
>
> It works fine.  I should have explained, already had the data.frame  
> with
> data in it, just wanted to add a string vector into the first column  
> of the
> data.frame, could not figure out how to do that.
?cbind   # generic, has a data.frame method

>
> Jim
> -- 
> View this message in context:
http://r.789695.n4.nabble.com/adding-a-row-of-names-to-data-frame-tp2278278p2279421.html
> Sent from the R help mailing list archive at Nabble.com.
>
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