[R] Very simple question about list components

[Steve Lianoglou]

Hi Clemontina,

On Fri, Sep 9, 2011 at 11:01 AM, Clemontina Alexander <ckalexa2 at ncsu.edu> wrote:
> I have a list 'ans' from the following code:
>
> tt <- rnorm(50)
> rr <- rnorm(50)
> ans <- lm(rr~tt)
>
> ans[1] is "$coefficients", ans[2] is "$residuals", ans[3] is
> "$effects", ... and so on up to ans[12]. Is there an easy way to
> display just these names and not the data they contain?

In this case, you can simply do:

R> names(ans)
 [1] "coefficients"  "residuals"     "effects"       "rank"
 [5] "fitted.values" "assign"        "qr"            "df.residual"
 [9] "xlevels"       "call"          "terms"         "model"

> saw my advisor type "ans$" and they were displayed, but when I tried
> it, it just goes to the next line waiting for input like this:
>
>> ans$

If you are in the R prompt and you hit <tab> twice after `ans$`, it
should show you the names of the elements in the `ans` list. If you
use Rstudio[1], the doube <tab> hit will give you a handy dropdown
menu list you can choose from.

HTH,
-steve

[1] For what it's worth, I'm not sure how far along in your R-learning
you are, but if I were starting out learning R today, I might pick
Rstudio as my IDE/interface of choice.

-- 
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