Re: st: e(wexp) versus e(wexp): different routines return different things

[Nick Cox <njcoxstata@gmail.com>]

I know; I was poking a little fun at your code, not the over-arching
problem. You
don't need to get rid of the = sign,  as you can use it.

Nick

On Sat, Aug 27, 2011 at 10:51 PM, Stas Kolenikov <skolenik@gmail.com> wrote:
> Nick,
>
> the original poster had an issue of some commands returning -e(wexp)-
> with an equal sign, and others, without it. So the equal sign had to
> be parsed out.
>
> On Sat, Aug 27, 2011 at 2:44 PM, Nick Cox <njcoxstata@gmail.com> wrote:
>> Too complicated :)
>>
>>  tempvar wvar
>>  if "`e(wexp)'" == "" generate byte `wvar' = 1
>> else generate double `wvar' `e(wexp)'
>>
>> On Sat, Aug 27, 2011 at 8:28 PM, Stas Kolenikov <skolenik@gmail.com> wrote:
>>> Oh those overqualified programmers working in Stata :). Regular
>>> expressions are an overkill for situation like this. You can achieve
>>> what you need with the string functions.
>>>
>>> tempvar wvar
>>> if "`e(wexp)'" == "" generate byte `wvar' = 1
>>> else {
>>>  local mywexp = subsinstr("`e(wexp)'","=","",1)
>>>  generate double `wvar' = `mywexp'
>>> }
>>>
>>> and then you can pass `wvar'.
>>>
>>> On Fri, Aug 26, 2011 at 8:49 PM, Rodini, Mark
>>> <mrodini@compasslexecon.com> wrote:
>>>> Greetings,
>>>>
>>>> I have a program which executes after I run an estimation procedure, and it does a collapse where weighting is an option.
>>>> Within the program is the following line:
>>>>
>>>>
>>>> if "`e(wexp)'" != "" {
>>>>                        collapse (mean) `y_sample' `xb_sample' [fw `e(wexp)']
>>>>                }
>>>>
>>>> I'm running an estimation using "reg" and one using "newey2".  Suppose the name of the weighting variable, should I opt to use it, is "mycount" so for example, I run:
>>>>
>>>> reg y high low cows [aw=mycount]
>>>>
>>>> and then execute the program.
>>>>
>>>>
>>>> Both estimation routines create as output an estimation "variable" called e(wexp).  Note that this is what is passed to the program as indicated above.
>>>>
>>>> Here is the kicker: reg returns e(wexp) as "= mycount", but newey2 returns e(wexp) as "mycount" (without the equals sign!)
>>>>
>>>> The reg version properly executes the program above, but newey2 gives an error about an inability to weight, since the syntax requires an equals sign.
>>>>
>>>> I have tried within the program to create a tempname or tempvar, assign e(wexp) to it and then tried running
>>>>
>>>> scalar `wts'=regexr(`e(wexp)',"=","")
>>>>
>>>> I then replace the `e(wexp)' in the program with `wts' and add an equals sign explicitly in the program.  The idea I was hoping for is that it would replace the "=" with nothing in the macro variable, if one were there.
>>>>
>>>> No matter how I try it, it fails, usually with a type mismatch error.  I tried adding double quotes, etc.  I am assuming that because I'm trying to pass it as a scalar, that is what bombs it.  Any thoughts?  I'm guessing it's something pretty basic --I'm kind of new to writing complicated programs which pass lots of stuff.
>>>
>>>
>>>
>>> --
>>> Stas Kolenikov, also found at http://stas.kolenikov.name
>>> Small print: I use this email account for mailing lists only.
>>>
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>>
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>
>
>
> --
> Stas Kolenikov, also found at http://stas.kolenikov.name
> Small print: I use this email account for mailing lists only.
>
> *
> *   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/
>

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