[R] Zero is not zero

Duncan Murdoch dmurdoch at pair.com
Wed May 28 21:02:25 CEST 2003

On Wed, 28 May 2003 10:48:08 -0400, you wrote:

>Hello, There:
>I read data from tab-delimted text file(1888.txt) in C:/temp, which has 
>thousands rows and 80 colulms, using read.delim("C:/temp/1888.txt"). when I 
>retrieved the numeric coulum which has real zero values and applies R buid-in 
>function such as mean( ), sum() and got a result of NA. It seems that R (R 
>1.6.2 in windows) considers zero as missing value (NA). Thus my question is 
>how to read the real zero as zero.

No, read.delim doesn't treat "0" as missing.  What is likely happening
is that some line of your file has a typo or other error in it, so it
doesn't look like a number, and the whole column is converted to
character mode.

To find where the error is, try as.numeric(x), where x is the column
containing your data, and it'll convert all the strings that don't
look like numbers to NA. 

Duncan Murdoch

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