See help(grepl) so using built in data frame CO2 this gets rows whose
Plant column start with Qn:
subset(CO2, grepl("^Qn", Plant))
On Tue, Jan 12, 2010 at 6:17 AM, Jean-Baptiste Combes
<jeanbaptiste.combes.a...@googlemail.com> wrote:
> Hello,
>
> I use R 2.10, and I am new in R (I used to use SAS and lately Stata), I am
> using XP.
>
> I have a data which has a data.frame format called x.df (read from a csv
> file). I want to take from this data observations for which the variable
> "Code" starts with an "R". I took all the Code and put them into a vector
> vec<-grep("R[A-Z][A-Z]",x.df$Code,value=TRUE)
>
> Then I created a function that is supposed to take all the lines in the my
> data x.df for which "Code" equals one value of "vec". See the code below
> where I created a loop to do that.
>
>> myfunc<-function(data,var2,var1)
> + {
> + i=1
> + while (i<632){
> + line<-subset(data,var2==var1[i])
> + if (i==1){
> + df<-line
> + df<-data.frame(df)
> + }
> + else {
> + line<-data.frame(line)
> + df<-rbind(df,line)
> + }
> + i<-i+1
> + }
> + fix(df)
> + }
>>
>
> The results of my program higly depend on the few last lines of the program.
> If I put "fix(df)", as above, the function opens a window with my data and
> it seems a sensible results (I have not checked in details but I barely have
> what I am suppose to get).
>> myfunc<-function(data,var2,var1)
> ...
> + }
> + df<-data.frame(df)
> + print(is.data.frame(df))
> + }
>> myfunc(x.df,x.df$Code,vec)
> [1] TRUE
>> print(is.data.frame(df))
> [1] FALSE
>
> In the case above I ask whether or not the "df" is a data.frame and the
> answer is true, when the program has ended, I ask again and the answer is
> false.
>
> Could anyone tell me what to do to get this data and could anyone tell me
> why those differences in the results?
>
>> as.data.frame(df)
> Erreur dans as.data.frame.default(df) :
> impossible de convertir automatiquement la classe "function" en un
> tableau de données (data.frame)
>>
>
> [[alternative HTML version deleted]]
>
>
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>
>
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