Export a list into a CSV or TXT file in R

Question

I understand that we cannot export a table if one of its elements is a list. I got a list in R and I want to export it into a CSV or TXT file. Here is the error message that I get when I execute this write.table command :

write.table(mylist,"test.txt",sep=";")

Error in .External2(C_writetable, x, file, nrow(x), p, rnames, sep, eol,  : 
unimplemented type 'list' in 'EncodeElement'

Here is the first element of my list :

$f10010_1
$f10010_1$mots
 [1] X16               ESPRESSO          TDISC             TASSIMO          
 [5] CARTE             NOIRE             A                 LAVAZZA          
 [9] MALONGO           MIO               MODO              123              
[13] CAPSULES          DOSES             78G               LONG             
[17] SPRESSO           CAFE              120G              CLASSIC          
[21] 104G              128G              AROMATIQUE        INTENSE          
[25] 112G              156G              520G              5X16             
[29] PROMO             TRIPACK           X24               126G             
[33] 16                4X16              APPASSIONATAMENTE APPASSIONATEMENTE
[37] BRESIL            CAPSUL            COLOMBIE          CORSE            
[41] CREMOSAMENTE      DELICATI          DELIZIOSAMENTE    DIVINAMENTE      
[45] DOLCEMENTE        EQI               GRAND             GRANDE           
[49] GT                GUATEMALA         HAITI             INTENSAMENTE     
[53] ITALIAN           MAGICAMENTE       MERE              MOKA78G          
[57] PETITS            PRODUCT           PURSMATIN         RESERVE          
[61] RISTRETO          SOAVEMENTE        STYLE             X36              
64 Levels: 104G 112G 120G 123 126G 128G 156G 16 4X16 520G 5X16 78G ... X36

$f10010_1$nblabel
 [1] 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32
[27] 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32
[53] 32 32 32 32 32 32 32 32 32 32 32 32
Levels: 32

$f10010_1$Freq
 [1] 18 16 16 15 14 14  9  9  9  9  9  8  8  8  7  7  7  6  5  5  3  3  3  3  2  2
[27]  2  2  2  2  2  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1
[53]  1  1  1  1  1  1  1  1  1  1  1  1

$f10010_1$pct
 [1] 0.56250 0.50000 0.50000 0.46875 0.43750 0.43750 0.28125 0.28125 0.28125
[10] 0.28125 0.28125 0.25000 0.25000 0.25000 0.21875 0.21875 0.21875 0.18750
[19] 0.15625 0.15625 0.09375 0.09375 0.09375 0.09375 0.06250 0.06250 0.06250
[28] 0.06250 0.06250 0.06250 0.06250 0.03125 0.03125 0.03125 0.03125 0.03125
[37] 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125
[46] 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125
[55] 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125
[64] 0.03125

Answer 1

Here is one way to write list to csv or other format file:

Input list:

test <- list(A=data.frame(m=1:3,n=letters[1:3]), B=1:5)

Export the list to a file:

library(data.table)
outputfile <- "test.csv" #output file name
sep <- "," #define the separator (related to format of the output file)
for(nam in names(test)){
  fwrite(list(nam), file=outputfile, sep=sep, append=T) #write names of the list elements
  ele <- test[[nam]]
  if(is.list(ele)) fwrite(ele, file=outputfile, sep=sep, append=T, col.names=T) else fwrite(data.frame(matrix(ele, nrow=1)), file=outputfile, append=T) #write elements of the list
  fwrite(list(NA), file=outputfile, append=T) #add an empty row to separate elements
}

Output looks like (I can't put picture here because of the level restrictions):

A
m,n
1,a
2,b
3,c

B
1,2,3,4,5

Answer 2

You can write your For loop to individually store dataframes from a list:

allocation = list()

for(i in 1:length(allocation)){
    write.csv(data.frame(allocation[[i]]), file = paste0(path, names(allocation)[i], '.csv'))
}

Answer 3

I export lists into YAML format with CPAN YAML package.

l <- list(a="1", b=1, c=list(a="1", b=1))
yaml::write_yaml(l, "list.yaml")

Bonus of YAML that it's a human readable text format so it's easy to read/share/import/etc

$ cat list.yaml
a: '1'
b: 1.0
c:
  a: '1'
  b: 1.0

Answer 4

cat(capture.output(print(my.list), file="test.txt"))

from R: Export and import a list to .txt file https://stackoverflow.com/users/1855677/42 is the only thing that worked for me. This outputs the list of lists as it is in the text file

Answer 5

using sink function :

sink("output.txt")
print(mylist)
sink()

Answer 6

I think the most straightforward way to do this is using capture.output, thus;

capture.output(summary(mylist), file = "My New File.txt")

Easy!

Answer 7

So essentially you have a list of lists, with mylist being the name of the main list and the first element being $f10010_1 which is printed out (and which contains 4 more lists).

I think the easiest way to do this is to use lapply with the addition of dataframe (assuming that each list inside each element of the main list (like the lists in $f10010_1) has the same length):

lapply(mylist, function(x) write.table( data.frame(x), 'test.csv'  , append= T, sep=',' ))

The above will convert $f10010_1 into a dataframe then do the same with every other element and append one below the other in 'test.csv'

You can also type ?write.table on your console to check what other arguments you need to pass when you write the table to a csv file e.g. whether you need row names or column names etc.

Answer 8

You can simply wrap your list as a data.frame (data.frame is in fact a special kind of list). Here is an example:

mylist = list() 
mylist[["a"]] = 1:10 
mylist[["b"]] = letters[1:10]
write.table(as.data.frame(mylist),file="mylist.csv", quote=F,sep=",",row.names=F)

or alternatively you can use write.csv (a wrapper around write.table). For the conversion of the list , you can use both as.data.frame(mylist) and data.frame(mylist).

To help in making a reproducible example, you can use functions like dput on your data.