You asked Stata to generate a variable if a condition was
true; whenever the condition is not true, the variable will
be missing:
> gen k=1 if loc2prov==1 & date<d(25aug2004)
> (97890 missing values generated)
>
What you want is probably
gen k = (loc2prov==1)&date<td(25aug2004)
now k will =1 if the condition is true, and equal 0
if the condition is not true.
If you want more than one region included, or a range of
dates included, see -inlist()- and -inrange()-; eg,
gen k = inlist(loc2prov,1,2)&inrange(date,td(25aug2003),td(25aug2004))
hope this helps,
Jeph
Ana Gabriela Guerrero Serdan wrote:
...
*then I compare and keep variables that belong to a specific region and within a specific date.
*since I have many regions I first create a dummy indicating which variables to keep:
gen k=1 if loc2prov==1 & date<d(25aug2004)
(97890 missing values generated)
replace k=1 if loc2prov==2 & date<d(25may2004)
(0 real changes made)
Why are missing values generated?
How can I tell stata to compare the date I have with another?
I also try creating separate variables for day, year and month but its not working
*
* 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/
