[R] replace "" to NA.

[jim holtman]

try this:


> test<-data.frame(
+ test1=c("","Hi","Hello"),
+ test2=c("Hi",NA,"Bye"),
+ test3=c("Hello","",""))
> test
  test1 test2 test3
1          Hi Hello
2    Hi  <NA>
3 Hello   Bye
>
> test[] <- lapply(test, function(x){
+     x[!is.na(x) & x == ''] <- NA
+     x
+ })
> test
  test1 test2 test3
1  <NA>    Hi Hello
2    Hi  <NA>  <NA>
3 Hello   Bye  <NA>
>

Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.


On Mon, Jan 6, 2014 at 6:57 AM, vikram ranga <babuawara at gmail.com> wrote:
> Dear All,
>
> I am bit stuck to a problem of replacing "" to NA.
> I have big data set but here is the toy example:-
>
> test<-data.frame(
> test1=c("","Hi","Hello"),
> test2=c("Hi","","Bye"),
> test3=c("Hello","",""))
>
> If the data as in above, I could change all "" to NA by this code:-
>
> for(i in 1:3){
> for(j in 1:3){
> if(test[j,i]==""){
> test[j,i]=NA
> }
> }
> }
>
> but the problem arises if data frame has NA at some places
>
> test<-data.frame(
> test1=c("","Hi","Hello"),
> test2=c("Hi",NA,"Bye"),
> test3=c("Hello","",""))
>
> the above loop script does not work on this data frame as NA is has
> logical class and does not return TRUE/FALSE.
>
> Can anyone provide some help?
>
> My sessionInfo is:
> R version 3.0.2 (2013-09-25)
> Platform: i386-w64-mingw32/i386 (32-bit)
>
> locale:
> [1] LC_COLLATE=English_India.1252  LC_CTYPE=English_India.1252
> LC_MONETARY=English_India.1252
> [4] LC_NUMERIC=C                   LC_TIME=English_India.1252
>
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods   base
>
> other attached packages:
>  [1] RColorBrewer_1.0-5 plotrix_3.5-2      foreign_0.8-57
> splancs_2.01-34    spatstat_1.34-0
>  [6] polyclip_1.1-0     tensor_1.5         abind_1.4-0
> deldir_0.1-1       mgcv_1.7-26
> [11] nlme_3.1-111       xlsx_0.5.1         xlsxjars_0.5.0
> rJava_0.9-4        ggplot2_0.9.3.1
> [16] rgdal_0.8-11       rgeos_0.3-2        maptools_0.8-27    sp_1.0-14
>
> loaded via a namespace (and not attached):
>  [1] colorspace_1.2-4 dichromat_2.0-0  digest_0.6.3     grid_3.0.2
>   gtable_0.1.2
>  [6] labeling_0.2     lattice_0.20-23  MASS_7.3-29      Matrix_1.0-14
>   munsell_0.4.2
> [11] plyr_1.8         proto_0.3-10     reshape2_1.2.2   scales_0.2.3
>   stringr_0.6.2
> [16] tcltk_3.0.2      tools_3.0.2
>
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