Re: st: Question about scalars

[Jeph Herrin <stata@spandrel.net>]

Yes, but look closely at

> . scalar e = d + a
> . scalar dir a d e // "e" is wrong
>           a =         10
>           d =  4.9458042
>           e =        131

You'll see that 4.94+10 = 131. Which is incorrect.

cheers,
Jeph

On 8/9/2010 2:15 PM, Sergiy Radyakin wrote:
> Hi, Steve,
>
> there might be something else in your program that prevents it from
> running. Both code fragments that you compare work fine in my Stata 9
> and Stata 11.
>
> Best, Sergiy
>
> . do "R:\TEMP\STD0h000000.tmp"
>
> . clear
>
> . scalar drop _all
>
> . scalar a = 10
>
> . scalar b = 20
>
> . scalar c = b + a
>
> . scalar dir
>           c =         30
>           b =         20
>           a =         10
>
> .
> . sysuse auto, clear
> (1978 Automobile Data)
>
> . reg mpg foreign
>
>        Source |       SS       df       MS              Number of obs =      74
> -------------+------------------------------           F(  1,    72) =   13.18
>         Model |  378.153515     1  378.153515           Prob>  F      =  0.0005
>      Residual |  2065.30594    72  28.6848048           R-squared     =  0.1548
> -------------+------------------------------           Adj R-squared =  0.1430
>         Total |  2443.45946    73  33.4720474           Root MSE      =  5.3558
>
> ------------------------------------------------------------------------------
>           mpg |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
> -------------+----------------------------------------------------------------
>       foreign |   4.945804   1.362162     3.63   0.001     2.230384    7.661225
>         _cons |   19.82692   .7427186    26.70   0.000     18.34634    21.30751
> ------------------------------------------------------------------------------
>
> . scalar d = _b[foreign]
>
> . scalar e = d + a
>
> . scalar dir a d e // "e" is wrong
>           a =         10
>           d =  4.9458042
>           e =        131
>
> .
> . tempname dd
>
> . scalar `dd' = _b[foreign]
>
> . scalar e = `dd' +a
>
> . scalar dir a `dd' e // "e" is /okay
>           a =         10
>    __000000 =  4.9458042
>           e =  14.945804
>
> .
> end of do-file
>
>
> On Mon, Aug 9, 2010 at 1:57 PM, Steve Samuels<sjsamuels@gmail.com>  wrote:
> > In the code below, I generate a scalar "d" from a regression result;
> > it looks okay, but trying to add it to another scalar doesn't work.
> > If, however I use a -tempname- , I get the right answer.  Could
> > someone explain to me why the first approach doesn't work and if
> > there's another approach that doesn't involve a -tempname-?
> >
> > Thanks,
> >
> > Steve
> >
> > ******************************
> > clear
> > scalar drop _all
> > scalar a = 10
> > scalar b = 20
> > scalar c = b + a
> > scalar dir
> >
> > sysuse auto, clear
> > reg mpg foreign
> > scalar d = _b[foreign]
> > scalar e = d + a
> > scalar dir a d e // "e" is wrong
> >
> > tempname dd
> > scalar `dd' = _b[foreign]
> > scalar e = `dd' +a
> > scalar dir a `dd' e // "e" is /okay
> > ****************************
> >
> > --
> > Steven Samuels
> > sjsamuels@gmail.com
> > 18 Cantine's Island
> > Saugerties NY 12477
> > USA
> > Voice: 845-246-0774
> > Fax:    206-202-4783
> >
> > *
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>
> *
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