R help - Dec 2008 - Want to create empty vectors inside a empty data frame

Hi All,
I want to create empty vectors inside an empty data frame.The name of the
vectors has to come dynamically.

For example if record_mean is my empty data frame,and i have say 4
categories,the category names for record mean data frame has to
recmeanC1,recmeanC2,recmeanC3,recmeanC4,which will be dynamically created
and which will again be inserted in my data frame's as column values.Each of
these should be also vectors later.Because later i want to use the cbind
function.

I wanted to do this:--
record_mean<-cbind(recmeanC1,recmeanC2,recmeanC3,recmeanC4)


where:--
record_mean=>is my initially created empty data frame------------------[i
can create this]
recmeanC1,recmeanC2,recmeanC3,recmeanC4=>the names i generate
dynamically,according to the categories i have [Caregories is again
collection of items...........[Able to do this]
recmeanC1=>this and others (like recmeanC2,recmeanC3,recmeanC4)=>should be
all vectors having the means of each records set item mean for a particular
category.....[]

Say i have 2 categories:--
Category1 say has==>i1,i2(say i have 10 records,i.e i1,i2 pair values)
Category2 say has==>i3,i4(10 records )
recmeanC1=>means of each i1,i2 value per record for category 1 as vector (i
keep adding rows of means ,using rbind)
recmeanC2=>means of each i3,i4 value per record for category 1 as vector


what i did was:--
cat_record_mean_dfs<-data.frame(r_m=NULL)
                #Preparing the number of categories mean storage dfs
                for(catno in 1:catnam_dataset_data_size[1])
                {
                   
cat_record_mean<-paste("recmeanC",1:catno,sep="")
                    cat_mean_vector<-as.vector(cat_record_mean)
                    #str(cat_mean_vector)
                    print(cat_mean_vector)
                    #cat_record_mean_dfs<-c(cat_record_mean)
                    #print("each category mean storage place")
                    #print(cat_record_mean_dfs)

#cat_record_mean_dfs<-rbind(cat_record_mean_dfs,data.frame(cat_record_mean=NULL))
# adding rows to the empty data frame

                }

Bottomline is ,can empty vectors be created inside an empty data frame?


-- 
Thanks
Moumita

	[[alternative HTML version deleted]]

Yes, you can add empty vectors, if you really need (I doubt you need):


  cat_record_mean_dfs <- data.frame()
  cat_record_mean_dfs[[paste("recmeanC", 1, sep="")]] <-
numeric(0)

Best,
Uwe Ligges



Moumita Das wrote:
> Hi All,
> I want to create empty vectors inside an empty data frame.The name of the
> vectors has to come dynamically.
> 
> For example if record_mean is my empty data frame,and i have say 4
> categories,the category names for record mean data frame has to
> recmeanC1,recmeanC2,recmeanC3,recmeanC4,which will be dynamically created
> and which will again be inserted in my data frame's as column
values.Each of
> these should be also vectors later.Because later i want to use the cbind
> function.
> 
> I wanted to do this:--
> record_mean<-cbind(recmeanC1,recmeanC2,recmeanC3,recmeanC4)
> 
> 
> where:--
> record_mean=>is my initially created empty data
frame------------------[i
> can create this]
> recmeanC1,recmeanC2,recmeanC3,recmeanC4=>the names i generate
> dynamically,according to the categories i have [Caregories is again
> collection of items...........[Able to do this]
> recmeanC1=>this and others (like
recmeanC2,recmeanC3,recmeanC4)=>should be
> all vectors having the means of each records set item mean for a particular
> category.....[]
> 
> Say i have 2 categories:--
> Category1 say has==>i1,i2(say i have 10 records,i.e i1,i2 pair values)
> Category2 say has==>i3,i4(10 records )
> recmeanC1=>means of each i1,i2 value per record for category 1 as vector
(i
> keep adding rows of means ,using rbind)
> recmeanC2=>means of each i3,i4 value per record for category 1 as vector
> 
> 
> what i did was:--
> cat_record_mean_dfs<-data.frame(r_m=NULL)
>                 #Preparing the number of categories mean storage dfs
>                 for(catno in 1:catnam_dataset_data_size[1])
>                 {
>                    
cat_record_mean<-paste("recmeanC",1:catno,sep="")
>                     cat_mean_vector<-as.vector(cat_record_mean)
>                     #str(cat_mean_vector)
>                     print(cat_mean_vector)
>                     #cat_record_mean_dfs<-c(cat_record_mean)
>                     #print("each category mean storage place")
>                     #print(cat_record_mean_dfs)
> 
>
#cat_record_mean_dfs<-rbind(cat_record_mean_dfs,data.frame(cat_record_mean=NULL))
> # adding rows to the empty data frame
> 
>                 }
> 
> Bottomline is ,can empty vectors be created inside an empty data frame?
> 
>