[R] error when extracting from a data frame

Suzanne.mertens suzanne.mertens at gmail.com
Tue Jan 17 22:17:41 CET 2012


(As a noob to R, this is my first posting - yes yes, groans all around...)

I'm trying to extract certain rows from a data frame. I used the following to import data from a CSV txt file.

	data <- read.table(file="data.txt", header=TRUE)

when I do this, my attempt to extract the data rows only from where the Station value equals 1…

	data.station1 <- data[data$Station == 1]

...is giving me the following error message:

	Error in `[.data.frame`(data, data
$Station == 1) : 
	  undefined columns selected


Bah. 
If I use names(data) I can see "Station" as a column name. 
And if I use str(data), the variable "Station" is coming up as integers including the value 1. 
And if I use data$Station, I see all station values, including the 1s. 
And if I use data[,"Station"] I do see all the Station values
And if I instead treat the Station values as characters, by using "1", I still get the "undefined" error. 

Could someone please correct me on my syntax? Or advise if perhaps I imported the data the wrong way? I'm working out of "A Beginner's Guide to R" and also looked through the R manual, and even tried this from  Google search:

	data.station1 <- data,("Station" == 1) ]

But that gave me an unwanted output: 
	data frame with 0 columns and 789 rows

Almost, but not quite. Please help?


Thank you,



- Suzanne
..........................................
suzanne.mertens at gmail.com
404-337-1533



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