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Re: st: RE: Efficient code to generate many date/time variables at once


From   Nick Cox <[email protected]>
To   "[email protected]" <[email protected]>
Subject   Re: st: RE: Efficient code to generate many date/time variables at once
Date   Wed, 26 Mar 2014 01:43:12 +0000

Just a small tweak to David's code will cut down on the number of variables.

foreach v of varlist drape curtain blind shade {
    local work string(dt_`v',"%td") + " " + tm_`v'
    gen double dt_tm_`v' = clock(`work',"DMYhm")
    format dt_tm_`v' %tc
}

In this example, omitting not only the equals sign but also delimiting
quotation marks are important details in the definition of the local
macro.

Nick
[email protected]

Radwin, David

> This sounds like a job for a simple -foreach- loop. You might specify the true varlist with a wildcard (dr*) or as a range of contiguous variables (drape - shade).
>
> foreach v of varlist drape curtain blind shade {
>         gen dt_tm_`v'_str = string(dt_`v',"%td") + " " + tm_`v'
>         gen double dt_tm_`v' = clock(dt_tm_`v'_str,"DMYhm")
>         format dt_tm_`v' %tc
>         }
>
> (This code is untested.) You could combine the two -generate- lines to increase computational efficiency, but I don't think that is the kind of efficiency you seek, and doing so probably isn't worth the hassle.
>
> For further reading, see Kit Baum's Why should you become a Stata programmer? (http://fmwww.bc.edu/GStat/docs/StataProg.pdf) or An Introduction to Stata Programming (http://www.stata-press.com/books/introduction-stata-programming).

Alison El Ayadi

>> I have to create a number of date/time variables using a %td formatted
>> date and a string time, which I generally do using the following code,
>> for each of the different time points -
>>
>> gen dt_tm_drape_str = string(dt_drape,"%td") + " " + tm_drape
>> gen double dt_tm_drape = clock(dt_tm_drape_str,"DMYhm")
>> format dt_tm_drape %tc
>>
>> I'd like to make my code more efficient by having it run through all
>> of the variables that I have, which are paired as dt_X and tm_X.  Any
>> suggestions on how to put together a program to do this?
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