Re: st: tab most frequently occurring

[Richard Goldstein <richgold@ix.netcom.com>]

thanks to Nick, Maarten and Scott; using these hints and code, I came up
with the following code which is called with two arguments (number of
rows wanted and variable name); note that the tab command gives exactly
what my client wants and so I have not bothered to generalize it:

qui clonevar `2'_2 = `2'
qui modes `2'_2, nmodes(`1') gen(flag`1')
qui replace `2'_2="all other" if flag`1'==0 & `2'!=""
ta `2'_2, sort mi
drop `2'_2 flag`1'

Rich

Nick Cox wrote:
> Thanks for the mention. -groups- is on SSC and was discussed in SJ 3-4. 
> 
> SJ-3-4  pr0011  . . . . . . . .  Speaking Stata: Problems with tables,
> Part II
>         . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  N.
> J. Cox
>         Q4/03   SJ 3(4):420--439                                 (no
> commands)
>         reviews three user-written commands (tabcount, makematrix,
>         and groups) as different approaches to tabulation problems
> 
> See also -modes-. 
> 
> SJ-9-4  sg113_2 . . . . . . . . . . . . . . . . . . . . .  Tabulation of
> modes
>         (help modes if installed) . . . . . . . . . . . . . . . . .  N.
> J. Cox
>         Q4/09   SJ 9(4):652
>         update to allow the generate() option to record in an
>         indicator variable of which observations contain values
>         matching any of the modes displayed
> 
> SJ-3-2  sg113_1 . . . . . . . . . . . . . . . . . .  Software update for
> modes
>         (help modes if installed) . . . . . . . . . . . . . . . . .  N.
> J. Cox
>         Q2/03   SJ 3(2):211
>         provides new option for specifying the number of modes to
>         be shown
> 
> STB-50  sg113 . . . . . . . . . . . . . . . . . . . . . .  Tabulation of
> modes
>         (help modes if installed) . . . . . . . . . . . . . . . . .  N.
> J. Cox
>         7/99    pp.26--27; STB Reprints Vol 9, pp.180--181
>         provides table of most frequent observations (modes)
> 
> However, to expand Scott's comment: Neither offers solutions to (b) or
> (c). Maarten has given some code. A hybrid of his code and -modes- would
> give you (b) and (c) as well. 
> 
> Nick 
> n.j.cox@durham.ac.uk 
> 
> Scott Merryman
> 
> Nick Cox's -groups- can handle (a):
> 
> . sysuse auto, clear
> (1978 Automobile Data)
> 
> . groups gear, select(5) order(h)
> 
>   +------------------------------------+
>   | gear_r~o   Freq.   Percent    Cum. |
>   |------------------------------------|
>   |     2.73       9     12.16   12.16 |
>   |     2.93       8     10.81   22.97 |
>   |     3.08       7      9.46   32.43 |
>   |     2.47       5      6.76   39.19 |
>   |     2.41       3      4.05   43.24 |
>   +------------------------------------+
> 
> . groups gear, select(freq>=3) order(h)
> 
>   +------------------------------------+
>   | gear_r~o   Freq.   Percent    Cum. |
>   |------------------------------------|
>   |     2.73       9     12.16   12.16 |
>   |     2.93       8     10.81   22.97 |
>   |     3.08       7      9.46   32.43 |
>   |     2.47       5      6.76   39.19 |
>   |     2.41       3      4.05   43.24 |
>   |------------------------------------|
>   |     3.05       3      4.05   47.30 |
>   |     3.54       3      4.05   51.35 |
>   |     3.78       3      4.05   55.41 |
>   +------------------------------------+
> 
> On Wed, Mar 17, 2010 at 8:30 AM, Richard Goldstein
> <richgold@ix.netcom.com> wrote:
>> I want to -tabulate- a variable with many (hundreds if not thousands
> of)
>> different values; but, I only want to see (a) the 20 (say) most
>> frequently occurring values and then (b) I want a row for "all others"
>> and then (c) I want a grand total row
>>
>> I have searched in various ways for already existing programs but, of
>> course, I may have missed something (as far as I can see, -fre- will
> not
>> do what I want but I would be happy to be shown that I was wrong)
>>
>> so, two questions:
>>
>> does anyone know of an already existing program for this?
>>
>> hints, etc. for writing my own would be welcome also if anyone has any
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