Error when exporting dataframe to text file in R

Question

I am trying to write a dataframe in R to a text file, however it is returning to following error:

Error in if (inherits(X[[j]], "data.frame") && ncol(xj) > 1L)
             X[[j]] <- as.matrix(X[[j]]) : 
  missing value where TRUE/FALSE needed

I used the following command for the export:

write.table(df, file ='dfname.txt', sep='\t' )

I have no idea what the problem could stem from. As far as "missing data where TRUE/FALSE is needed", I have only one column which contains TRUE/FALSE values, and none of these values are missing.

Contents of the dataframe:

> str(df)
'data.frame':   776 obs. of  15 variables:
 $ Age         : Factor w/ 4 levels "","A","J","SA": 2 2 2 2 2 2 2 2 2 2 ...
 $ Sex         : Factor w/ 2 levels "F","M": 1 1 1 1 2 2 2 2 2 2 ...
 $ Rep         : Factor w/ 11 levels "L","NR","NRF",..: 1 1 4 4 2 2 2 2 2 2 ...
 $ FA          : num  61.5 62.5 60.5 61 59.5 59.5 59.1 59.2 59.8 59.9 ...
 $ Mass        : num  20 19 16.5 17.5 NA 14 NA 23 19 18.5 ...
 $ Vir1        : num  999 999 999 999 999 999 999 999 999 999 ...
 $ Vir2        : num  999 999 999 999 999 999 999 999 999 999 ...
 $ Vir3        : num  40 999 999 999 999 999 999 999 999 999 ...
 $ Location    : Factor w/ 4 levels "Loc1",..: 4 4 4 4 4 4 2 2 2 2 ...
 $ Site        : Factor w/ 6 levels "A","B","C",..: 5 5 5 5 5 5 3 3 3 3 ...
 $ Date        : Date, format: "2010-08-30" "2010-08-30" ...
 $ Record      : int  35 34 39 49 69 38 145 112 125 140 ...
 $ SampleID    : Factor w/ 776 levels "AT1-A-F1","AT1-A-F10",..: 525 524 527 528
                                                                 529 526 111 78
                                                                 88 110 ...
 $ Vir1Inc     : logi  FALSE FALSE FALSE FALSE FALSE FALSE ...
 $ Month       :'data.frame':   776 obs. of  2 variables:
  ..$ Dates: Date, format: "2010-08-30" "2010-08-30" ...
  ..$ Month: Factor w/ 19 levels "Apr-2011","Aug-2010",..: 2 2 2 2 
                                                           2 2 18 18 18 18 ...

I hope I've given enough/the right information ...

Many thanks, Heather

Answer 1

An example to reproduce the error. I create a nested data.frame:

Month=data.frame(Dates= as.Date("2003-02-01") + 1:15,
                 Month=gl(12,2,15))
dd <- data.frame(Age=1:15)
dd$Month <- Month
str(dd)
'data.frame':   15 obs. of  2 variables:
 $ Age  : int  1 2 3 4 5 6 7 8 9 10 ...
 $ Month:'data.frame':  15 obs. of  2 variables:
  ..$ Dates: Date, format: "2003-02-02" "2003-02-03" "2003-02-04" ...
  ..$ Month: Factor w/ 12 levels "1","2","3","4",..: 1 1 2 2 3 3 4 4 5 5 ...

No I try to save it , I reproduce the error :

write.table(dd)
Error in if (inherits(X[[j]], "data.frame") && ncol(xj) > 1L) 
    X[[j]] <- as.matrix(X[[j]]) :  missing value where TRUE/FALSE needed

Without inverstigating, one option to remove the nested data.frame:

write.table(data.frame(subset(dd,select=-c(Month)),unclass(dd$Month)))