[R] a quick question about "rbinom"

[Steve Lianoglou]

A direct answer to your question:

On Wed, Jan 4, 2012 at 4:38 PM, lynn.tsai <vernal.lyn at gmail.com> wrote:
> Hello, I have the following code using rbinom, but I don't understand what
> *"+1"* means in the code. Could someone help? Thanks so much,
>
>> X1<-c("A","B")[rbinom(n,1,0.6)+1]
>> X2<-c("C","D")[rbinom(n,1,0.1)+1]

Is that the "+1" is adding 1 to the result returned from rbinom().

Look at what happens when you do:

R> c(1, 3, 5, 10) + 1

¡Tada!

If you're just learning R, you'll find it useful to deconstruct
"complex" commands into their "unit" pieces, if you catch my meaning
... look at what rbinom() returns, look at what it returns when you
"+1" it, then look at what you get when you use that whole expression
inside the "[]" to select elements in `c("A", "B")`

You will see the light ...

HTH,
-steve

-- 
Steve Lianoglou
Graduate Student: Computational Systems Biology
 | Memorial Sloan-Kettering Cancer Center
 | Weill Medical College of Cornell University
Contact Info: http://cbio.mskcc.org/~lianos/contact