R help - Jun 2008 - which question

Hello list,

I was trying to select a column of a data frame using the *which* command. I
was actually selecting the rows of the data frame using *which, *and then
displayed a certain column of it. The command that I was using is:
sequence=*mydata*[*which*(human[,3] %in% genes.sam.names),*9*]
In the above command, *mydata  *is my data frame, *9 *is the column which I
want to display. The rest are just other variables that I use. The
*which*command is supposed to retrieve the rows of interst. The rows
are well
retrieved, however, if for the certain row, column *9* is NA, the respective
element of column *10* is displayed. How can I fix that?

Thank you very much,
Eleni

	[[alternative HTML version deleted]]

Eleni Christodoulou <elenichri <at> gmail.com> writes:
> I was trying to select a column of a data frame using the *which* command.
I
> was actually selecting the rows of the data frame using *which, *and then
> displayed a certain column of it. The command that I was using is:
> sequence=*mydata*[*which*(human[,3] %in% genes.sam.names),*9*]
....
Please provide a running example. The *mydata* are difficult to read.


Dieter