through loop multiple Data.frames / can't save

Question

I made 8 data.frames through a loop but when I try to save it only one data.frame is saved.

`for(i in 1:8){id<-c(1,2,3,4,5,6,7,8)
i1<- c(rbinom(8,1,.5))
i2<-c(rbinom(8,1,.5))
rt1<-c(rnorm(8))
rt2<-c(rnorm(8))
df <- data.frame(id,i1,i2,rt1,rt2);print(df)}->X

I need all 8 data.frames saved in separate txt.files, but I can't to that with write.table if I can't save all 8 data.frames in a variable.

save your data.frames into a list: `for( i in ...) { ... myList[[i]] — lmo, Jun 07 '16 at 12:24

akrun · Accepted Answer · 2016-06-07T12:50:04.007

We can create this in a list

lst <-  replicate(8, {id<-c(1,2,3,4,5,6,7,8)
             i1<- rbinom(8,1,.5)
             i2<- rbinom(8,1,.5)
             rt1<-rnorm(8)
             rt2<- rnorm(8)
             df <- data.frame(id,i1,i2,rt1,rt2)},
                                    simplify = FALSE)

and then access each data.frame using [[

lst[[1]]
lst[[2]]

If we need to create 8 data.frame objects in the global environment, use list2env (not recommended though)

list2env(setNames(lst, paste0("df", seq_along(lst))), envir =.GlobalEnv)
df1
#  id i1 i2         rt1        rt2
#1  1  0  0 -0.10005874 -0.7554699
#2  2  0  1  0.73783083  0.9486937
#3  3  0  0  0.60071808 -0.6073825
#4  4  0  0  1.34181501 -0.7873832
#5  5  1  1  0.74039777 -0.4152928
#6  6  0  0  0.70413214  0.3182971
#7  7  0  1 -1.34215328  0.6912802
#8  8  1  1  0.08427694  0.6138306

df2
#  id i1 i2        rt1        rt2
#1  1  0  0 -0.5756818 -1.8153806
#2  2  0  1  0.6438000  0.4386427
#3  3  1  0  0.1849091  0.2079155
#4  4  1  1  1.0915329  0.9173109
#5  5  1  0 -0.6868610  0.2586526
#6  6  0  0  0.6588452  0.8982610
#7  7  1  1  0.7612920 -0.5889034
#8  8  1  1  0.7771745  0.4025183

If we need a for loop, either create an empty list of length N (here 8), and assign output from each iteration to it.

lst1 <- vector("list", 8)
for(i in 1:8){
      id<-c(1,2,3,4,5,6,7,8)
      i1<-  rbinom(8,1,.5)
      i2<-  rbinom(8,1,.5)
      rt1<- rnorm(8)
      rt2<- rnorm(8)
      lst1[[i]] <- data.frame(id,i1,i2,rt1,rt2)
   }

or instead of that, we can assign to a new object name in each iteration so that there will be 8 data.frame objects in the global environment

  for(i in 1:8){
      id<-c(1,2,3,4,5,6,7,8)
      i1<-  rbinom(8,1,.5)
      i2<-  rbinom(8,1,.5)
      rt1<- rnorm(8)
      rt2<- rnorm(8)
      assign(paste0("newdf", i), value= data.frame(id,i1,i2,rt1,rt2))
   }



newdf1
#  id i1 i2         rt1        rt2
#1  1  1  0  0.18472864  0.5929184
#2  2  1  1  0.72289366  0.9227808
#3  3  0  0  1.67604392  1.1759845
#4  4  0  0 -1.37200571 -1.4740593
#5  5  1  0 -1.60339952  0.7562232
#6  6  1  1 -2.33245352  0.9699605
#7  7  0  0  0.05202936  0.9604707
#8  8  0  0 -0.99444913  0.5079725

Yeah thanks for your help , thats nearly how I wanted it , but I need to create this data-frames with a loop command — J.Goodcat, Jun 07 '16 at 12:40
thanks this was a big help! I´ve got one little question though how can i save this 8 dataframes in 8diffrent text-files with write.table ? I only get errors when i try it — J.Goodcat, Jun 07 '16 at 12:57
@J.Goodcat In that case, you don't need separate objects in the global environment. Use the `list`. i.e. `lst2 — akrun, Jun 07 '16 at 13:01
If I write this command R says something ist missing .I only need to save this 8 Dataframes in seperate txt-files with write data and after that combine this 8 dataframes with a second loop command to one Data-frame — J.Goodcat, Jun 07 '16 at 13:17

through loop multiple Data.frames / can't save

1 Answers1