
Hi,

I am preparing a quite huge database in Excel, I replaced the empty cells with "NA", I formatted it like text, and saved the file like a *.txt.
After, in R:

data<-read.table("myfile.txt",header=T,sep="\t")
edit(data)

When doing this I can see that some columns are OK and they have NA cells, but other columns are not (there are empty cells where there should be NAs). 
Surprisingly (at least to me), when I close the "edit window" I can see all the data in the "R console" (automatically closing that windows makes starting the visualization of those data in the same R console window) and there are not empty cells but, nevertheless, some columns have NA values but other ones have <NA> values.
Why?
Could it possibly cause any problem to the analysis?  

Thanks
Best wishes

Simone
 		 	   		  
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