[R] create data frame(s) from a list with different numbers of rows

[jim holtman]

Instead of:

sample.df1 <-data.frame(list.sample[[1]])
sample.df2 <-data.frame(list.sample[[2]])
sample.df3 <-data.frame(list.sample[[3]])
sample.df4 <-data.frame(list.sample[[4]])
sample.df5 <-data.frame(list.sample[[5]])
sample.df6 <-data.frame(list.sample[[6]])

use 'lapply' to create a list of dataframe:

> lapply(list.sample, data.frame)
[[1]]
    Var1 Freq
1 1  1 1  0.5
1 3  1 3  0.5
1 4  1 4  0.5
2 1  2 1  0.5
2 2  2 2  0.5
2 3  2 3  0.5
2 4  2 4  1.0
3 2  3 2  1.5
3 3  3 3  0.5
...........

You will have a list of 6 dataframes that you can then use.

On 9/27/07, Luke Neraas <lukasneraas.r at gmail.com> wrote:
> # Hello,
>
>
> # I have a list with 6 categories and with different numbers of rows.
> # I would like to change each of them into a unique data frame in order to
> match
> # values with other data frames and perform some calculations.
> # Or I could make each category or list element have the same number of rows
> and create one large data.frame.
> # below is a creation of a sample list
> # I apologize for the length in creating the list it is the only way i could
> figure
> # out how to convey my puzzle. If you scroll down you will find it as "
> list.sample."
>
>
> Loci<-4
> Pairwise<- (Loci*(Loci-1))/2
>
> #Creation of list elements
>
> c1<- c(1,4,3,2,4,1,3,2,4,3)
> c2<- c(2,4,3,4,2,3,4,1,3,2)
> c3<- c(1,3,2,4,4,3,4,4,2,2)
> c4<- c(2,3,2,3,1,3,2,4,4,3)
> c5<- c(1,2,1,1,2,2,3,3,2,1)
> c6<- c(3,2,4,3,1,1,2,3,3,4)
> c7<- c(1,2,1,2,3,2,3,2,1,2)
> c8<- c(1,2,2,3,2,3,3,4,1,2)
>
> List.elements<-cbind(c1,c2,c3,c4,c5,c6,c7,c8)
>
>
> #Locus 1
> L1.pairwise.columns <- matrix(3:ncol(List.elements), byrow=TRUE, ncol=2)
>
> Loc1.gamete.counts<- apply(L1.pairwise.columns , 1, function(.row){
>                     paste(List.elements[,1:2], List.elements[,.row])
>                 })
> #Locus2
> L2.pairwise.columns <- matrix(5:ncol(List.elements), byrow=TRUE, ncol=2)
>
> Loc2.gamete.counts<- apply(L2.pairwise.columns , 1, function(.row){
>                     paste(List.elements[,3:4], List.elements[,.row])
>                      })
> #Locus3
> L3.pairwise.columns <- matrix(7:ncol(List.elements), byrow=TRUE, ncol=2)
>
> Loc3.gamete.counts<- apply(L3.pairwise.columns , 1, function(.row){
>                     paste(List.elements[,5:6], List.elements[,.row])
>                    })
> ##Creation of the List
>
> Gamete.pairs<-cbind(Loc1.gamete.counts,Loc2.gamete.counts,Loc3.gamete.counts
> )
> Gamete.pairs
>
> Gamete.list<-list(1,2,3,4,5,6)
>
> for (i in 1:Pairwise){
>    Gamete.list[[i]]<-table(Gamete.pairs[,i])
>            }
> Gamete.list
>
> #### Gamete Frequency
>
> list.sample<-list(1,2,3,4,5,6)
>
> for (j in 1:Pairwise){
>    list.sample[[j]]<- Gamete.list[[j]]/(2*Genetic.Sample.Size)
>            }
>
> ########  Here is the Sample List
>
> list.sample
>
>
> # I would like to have a flexible way to turn all six element in my list
> # into separate data frames so i can do some calculations
> # the only way i can figure out how to do this is "one by one" in very
> clunky fashion.
> # here is an example of my code
>
> sample.df1 <-data.frame(list.sample[[1]])
> sample.df2 <-data.frame(list.sample[[2]])
> sample.df3 <-data.frame(list.sample[[3]])
> sample.df4 <-data.frame(list.sample[[4]])
> sample.df5 <-data.frame(list.sample[[5]])
> sample.df6 <-data.frame(list.sample[[6]])
>
>
> sample.df1
> sample.df2
> sample.df3
> sample.df4
> sample.df5
> sample.df6
>
> # In the future i will have up to 1,200 of these small dataframes to create.
> # is there a way to loop through the list and create many small data
> frames??
> # or perhaps make each of the  list elements the same length and create one
> large data frame??
>
> # any help or ideas would be greatly appreciated
>
> # thanks in advance
>
> Luke Neraas
>
> lukasneraas.r at gmail.com
>
> University of Alaska Fairbanks
> School of Fisheries and Ocean Sciences
> 11120 Glacier Highway
> UAF Fisheries Division
> Juneau, AK 99801
>
>        [[alternative HTML version deleted]]
>
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>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

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