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Hi Etienne
It is not so elegant, bu I think that work.
colname.list<-paste("A",1:5,sep="")
df<-data.frame(matrix(matrix(rep(1,length(colname.list)),1),1))
df
colnames(df)<-colname.list
df
df<-df[-1,]
df
Cheers,
Miltinho Astronauta
Brazil
On 8/4/08, Etienne Bellemare Racine <etiennebr@gmail.com>
wrote:>
> Hi all,
>
> Given a string list,
> > paste("A",1:5,sep="")
> [1] "A1" "A2" "A3" "A4"
"A5"
>
> I would like to create an empty data frame using that list as the
> header, so I can access my data frame column using,
> > df [ list [ i ] ]
>
> Anyone ?
>
> Thanks,
> Etienne
>
>
>
> [[alternative HTML version deleted]]
>
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on 08/04/2008 07:40 PM Etienne Bellemare Racine wrote:> Hi all, > > Given a string list, > > paste("A",1:5,sep="") > [1] "A1" "A2" "A3" "A4" "A5" > > I would like to create an empty data frame using that list as the > header, so I can access my data frame column using, > > df [ list [ i ] ] > > Anyone ? > > Thanks, > EtienneYou don't indicate how you might want the column classes to be defined, but: Cols <- paste("A", 1:5, sep="") > Cols [1] "A1" "A2" "A3" "A4" "A5" DF <- read.table(textConnection(""), col.names = Cols) > DF [1] A1 A2 A3 A4 A5 <0 rows> (or 0-length row.names) > str(DF) 'data.frame': 0 obs. of 5 variables: $ A1: logi $ A2: logi $ A3: logi $ A4: logi $ A5: logi Or, as an example of using 'colClasses': DF <- read.table(textConnection(""), col.names = Cols, colClasses = "character") > str(DF) 'data.frame': 0 obs. of 5 variables: $ A1: chr $ A2: chr $ A3: chr $ A4: chr $ A5: chr Note from the "Value" section of ?read.table: Empty input is an error unless col.names is specified, when a 0-row data frame is returned: similarly giving just a header line if header = TRUE results in a 0-row data frame. Note that in either case tthe columns will logical unless colClasses was supplied. In this case, I am supplying an empty value using textConnection() in place of the typical source file name. HTH, Marc Schwartz