Outputting a Dataframe in R to a .csv

Question

So I'm trying to write a .csv file based on a data frame in R, but for some reason I keep getting the following error:

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

This is what traceback() is giving:

5: write.table(df, file = "df.csv", col.names = NA, 
       sep = ",", dec = ".", qmethod = "double")
4: eval(expr, envir, enclos)
3: eval(expr, p)
2: eval.parent(Call)
1: write.csv(df, file = "df.csv")

Any solution?

Check that your `df` actually is a data frame, and not the F density function (`?df`). — Hong Ooi, Jun 25 '13 at 07:21

SummerEla · Answer 1 · 2016-04-21T18:13:15.070

31

You can also coerce data frames directly in R:

my.df <- data.frame(lapply(old.df, as.character), stringsAsFactors=FALSE)

CAVEAT: this will coerce your entire dataframe to whatever type you specify. For example, if you want to coerce your dataframe to number, you would replace 'as.characater' with 'as.numeric':

 my.df <- data.frame(lapply(old.df, as.numeric), stringsAsFactors=FALSE)

edited Apr 21 '16 at 18:13

answered Aug 20 '14 at 21:51

SummerEla

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@SummerEla, what if the list is not of the same length : it gaves me `arguments imply differing number of rows: 2, 3` error – academic.user May 11 '15 at 21:33
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@academic.user For data frames, R generally works under the assumption that all the columns you put in a data frame are going to be the same length. For help wrangling your data, try something like this: http://stackoverflow.com/questions/15753091/convert-mixed-length-named-list-to-data-frame – SummerEla May 12 '15 at 22:15
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This worked for me as well, with a caveat that `as.character` changes everything to a character column, messing up the digits in my decimals. If you're working with a numeric data.frame try `my.df <- data.frame(lapply(old.df, as.numeric), stringsAsFactors=FALSE)` – slammaster Sep 16 '15 at 14:24
Thanks, @slammaster; I updated my answer to incorporate your point. – SummerEla Apr 21 '16 at 18:13

score 20 · Accepted Answer · answered Jun 25 '13 at 07:21

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One of your columns is of type list, so the data.frame is no longer 2-dimensional and can't be exported to a 2d csv-file.

If you still want to store the list in the resulting output, you might transform it to JSON first. So it becomes an column of type "character" which can be easily exported as one column to csv.

answered Jun 25 '13 at 07:21

Marcel Hebing

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Thanks, that fixed it. Working with dates in R is a little wonky – riders994 Jun 25 '13 at 07:57

score 3 · Answer 3 · answered Jul 15 '16 at 20:47

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I just had the same issue and instead of using as.character() or as.numeric(), I used as.matrix(), and it kept my character variables character, and my numeric variables numeric, and output the .csv file like a dream.

answered Jul 15 '16 at 20:47

Andy Bogart

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Outputting a Dataframe in R to a .csv

3 Answers3

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