reshape or what?

[River Huang]

Dear All, I found this question here (http://bbs.pinggu.org/thread-6513949-1-1.html). The data is

* Example generated by -dataex-. To install: ssc install dataex
clear
input int id str10 date float vol
 22 "2016-03-21" .052813
 22 "2016-03-22" .052454
 22 "2016-03-23" .052408
 22 "2016-03-24" .047639
153 "2016-03-22" .050336
153 "2016-03-23" .050088
153 "2016-03-24" .043589
153 "2016-03-25" .042855
521 "2016-03-20" .037602
521 "2016-03-21"  .03761
521 "2016-03-22" .037194
521 "2016-03-23"     .03
end

and the purpose to transform the data to be something like

input int id22 str10 date22 float vol22 int id153 str10 date153 float vol153 int id521 str10 date521 float vol521
  .  ""            .       .  ""  .                   521 "2016-03-20" .037602
 22 "2016-03-21" .052813   .  ""  .                   521 "2016-03-21"  .03761
 22 "2016-03-22" .052454   153 "2016-03-22" .050336   521 "2016-03-22" .037194
 22 "2016-03-23" .052408   153 "2016-03-23" .050088   521 "2016-03-23"     .03
 22 "2016-03-24" .047639   153 "2016-03-24" .043589   .  ""  .
 .  ""  .                  153 "2016-03-25" .042855   .  ""  .
end

Basically, the data one the same date should be on the same row! Any suggestion is appreciated.

[Nick Cox]

Bad idea. The present data layout (structure, format) is fine for the great majority of Stata purposes.

If one did reshape, you certainly wouldn't need the same dates again and again in two or more variables.

Sorry, I can't read the original, but perhaps you can tell us if there was a specific reason given for wanting this.

String dates need to be fixed for most Stata purposes.

[River Huang]

Dear Nick, I share with your concern. However, it seems to me the question asker (for unknown reasons) wants to regress vol22 on vol153 and vol521.

[Nick Cox]

OK. So the reshape is one line, left as an exercise to the reader.

[River Huang]

Dear Nick, Thanks, but it is not that straightforward to me (I must miss something!).

[William Lisowski]

. reshape wide vol, i(date) j(id)
(note: j = 22 153 521)

Data                               long   ->   wide
-----------------------------------------------------------------------------
Number of obs.                       12   ->       6
Number of variables                   3   ->       4
j variable (3 values)                id   ->   (dropped)
xij variables:
                                    vol   ->   vol22 vol153 vol521
-----------------------------------------------------------------------------

. list, clean noobs

          date     vol22    vol153    vol521  
    2016-03-20         .         .   .037602  
    2016-03-21   .052813         .    .03761  
    2016-03-22   .052454   .050336   .037194  
    2016-03-23   .052408   .050088       .03  
    2016-03-24   .047639   .043589         .  
    2016-03-25         .   .042855         .

[River Huang]

Dear William, Thank you so much.