Question about extracting certain rows from one column in a data.frame
On Mon, May 28, 2012 at 3:16 PM, Kelly Cool <kellycool79 at yahoo.com> wrote:
I was wondering if there was a quick way to extract out certain rows from a data set in R? I have a data.frame, LOG, ?where in one column, sample_data_tx, there is a list of 62 different types of treatment. I've sub-selected the rows that contain the names, "PLO" and "NOY" to make a new vector which I call, Test. ?Here's my code so far, ##In LOG data set, Test set is every treatment, PLO and NOY## ##Select rows in the LOG data set that contain Noy## Noy <- which(LOG$sample_data_tx == "Noy") ##Select rows in the LOG data set that contain PLO## PLO <- which(LOG$sample_data_tx == "PLO") ##Make Test Set## ?Test <- c(Noy, PLO)
Test
[1] ?8 24 50 23 29 46 55 Within the data.frame, LOG, I would like to now make another vector, "Training", that contains every row in the column, "sample_data_tx", except rows 8, 24, 50, 23, 29, 46, 55.
I think you're looking for negative indexing (which is, in my opinion,
pretty much the best thing ever)
E.g.,
x <- letters[1:10]
x[1:3] # First three letters
x[-(1:3)] # Without the first three letters
x[-4] # Leave out "d"
etc.
Of course, for this case, you might also want the subset function:
subset(LOG, sample_data_tx %in% c("Noy","PLO"))
"Test" is also an integer and I am hoping to make a hierarchical plot with both the "Test" and "Training" vectors so I am not sure if I first need to convert the data from integer to numeric form?
No, almost always these sorts of conversions will be taken care of you automatically Best, Michael
I am new to R so all help is appreciated. Thanks in advance. ? ? ? ?[[alternative HTML version deleted]]
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