Bookmark and Share

Notice: On March 31, it was announced that Statalist is moving from an email list to a forum. The old list will shut down at the end of May, and its replacement, statalist.org is already up and running.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: st: calculating cumulative values of other observations


From   Nick Cox <njcoxstata@gmail.com>
To   "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu>
Subject   Re: st: calculating cumulative values of other observations
Date   Sat, 7 Apr 2012 09:08:49 +0100

Why not

bysort id activity (time): gen priorhrs = sum(time) - time

Nick



On 7 Apr 2012, at 02:29, Eric Booth <eric.a.booth@gmail.com> wrote:

<>


******************!

//input example data//
clear
inp ID    str18 date  str4 activity hours
1    20071230  A    10
1    20071122  A    11
2    20071120  A    5
3    20071210  B    6
3    20071111  B    24
3    20071130  F    20
3    20070511  B    49
4    20070611  A    50
end

//cleanup//
g date2 = date(date, "YMD")
format date2 %td
sort ID activity date2

//gen prior hours var//
g priorhrs = 0
forval n = 1/`=_N' {
by ID activity: replace priorhrs =  ///
   priorhrs + hours[_n-`n']  ///
   if date2[_n]>=date2[_n-`n']
   }
 l
********************!


- Eric

__
Eric A. Booth
Public Policy Research Institute
Texas A&M University
ebooth@ppri.tamu.edu
+979.845.6754


On Apr 6, 2012, at 6:09 PM, KOTa wrote:

Hi all,

i have a data looking like this:

ID date activity hours prior result should be:
1    20071230      A    10       ?    <--    11
1    20071122            A    11       ?        0
2    20071120            A    5       ?        0
3    20071210            B    6       ?        73
3    20071111            B    24       ?        49
3    20071130            F    20       ?        0
3    20070511            B    49       ?        0
4    20070611            A    50       ?        0

(better picture here http://gyazo.com/5dc1218534d8b185ab22989069034b8a.png )

i need to fill "prior" column with following:
- amount of hours spent on same activity by same user(ID) prior to
date of current activity.

example:
in case of observation 4(line 4) activity is B, so prior = sum of
hours spent on activity B before it took place (i.e. before 20071210)
there are 2 such observations, one with 49 hour, another with 24.
Therefore, prior = 24+49=73.


any suggestions how to make this simple?

i was thinking to use "sort" and "by:", but i can't figure out how to
conditionally("if")  sum up values from different observations into
"prior" var
its not a first time i encounter similar problem and always took some
way around, but this time i decided to ask, maybe there is proper,
simple way to do this

thank you in advance

K.
*
*   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/
*
*   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/


© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   Site index