How to access single elements in a table in R

How do I grab elements from a table in R?

My data looks like this:

         V1     V2
1      12.448 13.919
2      22.242  4.606
3      24.509  0.176

etc...

I basically just want to grab elements individually. I'm getting confused with all the R termi开发者_如何学编程nology, like vectors, and I just want to be able to get at the individual elements.

Is there a function where I can just do like data[v1][1] and get the element in row 1 column 1?

Try

data[1, "V1"]  # Row first, quoted column name second, and case does matter

Further note: Terminology in discussing R can be crucial and sometimes tricky. Using the term "table" to refer to that structure leaves open the possibility that it was either a 'table'-classed, or a 'matrix'-classed, or a 'data.frame'-classed object. The answer above would succeed with any of them, while @BenBolker's suggestion below would only succeed with a 'data.frame'-classed object.

There is a ton of free introductory material for beginners in R: CRAN: Contributed Documentation

?"[" pretty much covers the various ways of accessing elements of things.

Under usage it lists these:

x[i]
x[i, j, ... , drop = TRUE]
x[[i, exact = TRUE]]
x[[i, j, ..., exact = TRUE]]
x$name
getElement(object, name)

x[i] <- value
x[i, j, ...] <- value
x[[i]] <- value
x$i <- value

The second item is sufficient for your purpose

Under Arguments it points out that with [ the arguments i and j can be numeric, character or logical

So these work:

data[1,1]
data[1,"V1"]

As does this:

data$V1[1]

and keeping in mind a data frame is a list of vectors:

data[[1]][1]
data[["V1"]][1]

will also both work.

So that's a few things to be going on with. I suggest you type in the examples at the bottom of the help page one line at a time (yes, actually type the whole thing in one line at a time and see what they all do, you'll pick up stuff very quickly and the typing rather than copypasting is an important part of helping to commit it to memory.)

Maybe not so perfect as above ones, but I guess this is what you were looking for.

data[1:1,3:3]    #works with positive integers
data[1:1, -3:-3] #does not work, gives the entire 1st row without the 3rd element
data[i:i,j:j]    #given that i and j are positive integers

Here indexing will work from 1, i.e,

data[1:1,1:1]    #means the top-leftmost element