While working with date variables in STATA, I encountered an interesting problem. There is a date variable and there are hundreds of other common variables. I have to find out the initial and ending date for each variables based on that single date variable. Such as, if a variable has all missing observations up to 1st December but at least 1 respondent responds on 2 December, then the initial date for that variable would be 2 December and so on. But I would like to request for clues about how this can be done for all the variables through STATA command (or any other software) and not by looking in the actual data which is gruesome for a large dataset.
I am replying on my own question. I know the traditional method of doing it. But that is truly gruesome as there are around 2500 variables. To give command for each is time consuming. If anyone is wondering how to do it (traditional method), this is how it is:
First copy the code that you can find in: http://fmwww.bc.edu/repec/bocode/s/summdate.ado
Paste and run in your STATA.
If X is a date variable and V1,V2,V3,.........etc. are other variables, then for finding the initial and final date, the command is:
summdate X if V1!=.
and so on. It will give you the maximum and minimum dates. But there can be other ways of doing it as well.
But what I need is a loop such as using 'foreach' command. Any clues??
Have ever tried: Sort data by date, create first_ and last_ variables for each variable?
Questions like this are best sent to Statalist (http://www.statalist.org/). However, the following code should cover it:
foreach v of varlist V1-V999 {
summdate X if `v'
@Ming and @Paul, Thank you for your replies. I'll try this code and see how it fares.
@Paul- This command works fine. It produces results without the names of the variables. Is it also possible to do that? I mean the name of the variables above each outputs.
Easy enough:
foreach v of varlist V1-V999 {
di "Results for `v'"
summdate X if `v'
Thank you @Paul for the codes. They are going to save a lot of time for me.
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