I recently had this puzzle with time formats and tabulations.
I was generating a month variable and initially got the expected
results. However, when I changed to a display format that was wider,
both tabulate and table applied inappropriate time formats to the row
headings.
. gen mdos=mofd(dos)
. levelsof mdos
555 556 557 558 559 560 561 562 563 564 565 566
. format mdos %tmCY!mn
. list dos mdos in 1/3
+---------------------+
| dos mdos |
|---------------------|
1. | 09apr2006 2006m4 |
2. | 10apr2006 2006m4 |
3. | 11apr2006 2006m4 |
+---------------------+
. tab mdos
mdos | Freq. Percent Cum.
------------+-----------------------------------
2006m4 | 170 7.54 7.54
2006m5 | 189 8.38 15.92
2006m6 | 221 9.80 25.72
...
. format mdos %tmM_CY
. list mdos in 1/3
+------------+
| mdos |
|------------|
1. | April 2006 |
2. | April 2006 |
3. | April 2006 |
+------------+
. tab mdos
mdos | Freq. Percent Cum.
------------+-----------------------------------
09jul1961 | 170 7.54 7.54
10jul1961 | 189 8.38 15.92
11jul1961 | 221 9.80 25.72
...
. table mdos, stubwidth(20)
---------------------------------
mdos | Freq.
---------------------+-----------
09jul1961 | 170
10jul1961 | 189
11jul1961 | 221
...
Some experimentation with the width of the display format demonstrates
that at width 9 the display works properly but with a width of >9 it
reverts to a %d format rather than a %tm format. I've shown this with
adding some padded spaces to the display format.
* 9 spaces
. format mdos %tmCY__l
. tab mdos
mdos | Freq. Percent Cum.
------------+-----------------------------------
2006 apr | 170 7.54 7.54
2006 may | 189 8.38 15.92
2006 jun | 221 9.80 25.72
...
* 10 spaces
. format mdos %tmCY___l
. tab mdos
mdos | Freq. Percent Cum.
------------+-----------------------------------
09jul1961 | 170 7.54 7.54
10jul1961 | 189 8.38 15.92
11jul1961 | 221 9.80 25.72
...
-tabulate- is a built in command, but -table- is implemented as an ado
and uses -tabdisp- to do the final table display. Interestingly,
-tabdisp- exhibits the same behaviour:
. format mdos %tmCY___m
. tabdisp mdos, cell(hosp)
-----------------------
mdos | Hospital
-----------+-----------
2006 Apr | 1
2006 May | 0
2006 Jun | 0
...
. format mdos %tmCY____m
. tabdisp mdos, cell(hosp)
----------------------
mdos | Hospital
----------+-----------
09jul1961 | 1
10jul1961 | 0
11jul1961 | 0
...
Hopefully I have provided enough detail and examples so that others
may reproduce this and determine if this is indeed a bug.
------------------------
Platform & Version info:
Windows XP sp2
Stata executable
folder: K:\Stata9SE\
name of file: wsestata.exe
currently installed: 20 Jul 2007
latest available: 20 Jul 2007
--
David Elliott
*
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