If you need a oneliner, you could
. ssc install moremata
and then type
. matrix A = (2,1\3,2\-2,2)
. mata: mm_plot(st_matrix("A"))
See
. help mata mm_plot()
for details.
ben
On Mon, Jan 12, 2009 at 6:30 PM, Jacob Wegelin <[email protected]> wrote:
> Can one easily plot two columns of a Stata matrix against each other?
>
> Details of this question:
>
> In Stata, we can only have one dataset "open" at a time. Yet it is
> possible to have several matrices available at the same time.
>
> Suppose I have a matrix like the following:
>
> . matrix A = (2,1\3,2\-2,2)
>
> . matrix list A
>
> A[3,2]
> c1 c2
> r1 2 1
> r2 3 2
> r3 -2 2
>
> and I'd like to create, say, a scatterplot of c2 vs c1.
>
> One approach is to save the current data temporarily, turn the matrix
> into a dataset, and use the familiar twoway command:
>
> . save tmp, replace
> file tmp.dta saved
>
> . clear
>
> . svmat A , names(col)
> number of observations will be reset to 3
> Press any key to continue, or Break to abort
> obs was 0, now 3
>
> . list
>
> +---------+
> | c1 c2 |
> |---------|
> 1. | 2 1 |
> 2. | 3 2 |
> 3. | -2 2 |
> +---------+
>
> . twoway (scatter c2 c1)
>
>
> But is there a way to approach it using just the matrix, without
> disturbing the dataset in memory?
>
> More generally, where should I look to educate myself on this kind of
> stuff? Would the best information be found in the mata manual, or ...?
>
> Bigger picture: Stata compares favorably with R (www.r-project.org) in
> several ways. It tends to be more user-friendly, and certain tools
> frequently used in conventional data analysis, such as
> cross-tabulation, are standard in Stata, unlike in R. Thus one can
> document one's data analysis with less ambiguity; -tabulate- means
> -tabulate- because the function was not pulled from some private
> researcher's library.
>
> On the other hand, in R the number of matrices that one can hold in
> memory and manipulate in the same session is limited only by the
> memory of one's computer. Also, in R one can hold several *data
> frames* in memory. A data frame is more like a Stata dataset than a
> Stata matrix; its columns can be of any type (e.g., string,
> qualitative, numeric). If it were possible to manipulate matrices in
> Stata, then Stata would compete with R in this area. Stata would be
> especially competitive if matrices in Stata were generalized to allow
> the columns of any matrix to be of arbitrary types--e.g., an "ID"
> column which is str10, an "Age" column which is integer, etc.
>
> Thanks for any pointers, including where I should be reading or what
> Stata course I should sign up for
>
> Jacob Wegelin
> *
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
