Re: st: local and loops

[Jeph Herrin <stata@spandrel.net>]

I see the same behaviour as Matt - the -local- assignment produces different results when within the loop than when 
without it. It is the same difference whether typed interactively or run from a -do- file.
Jeph


On 8/20/2013 3:21 PM, Nick Cox wrote:
> Interesting. For the record, I am currently using Stata 10.1 on a
> Mesolithic machine. It trims both inside and outside loops.
>
> Nick
> njcoxstata@gmail.com
>
>
> On 20 August 2013 20:17, Matthew White <mwhite@poverty-action.org> wrote:
> > Hi Nick,
> >
> > Thanks for your reply.
> >
> > There were supposed to be exactly two spaces between 1 and 2, and the
> > second string specified to -strpos()- was supposed to be two
> > consecutive spaces.
> >
> > Outside of a loop, the internal spaces in `foo' are actually preserved
> > on my computer, even without the double quotes:
> >
> > . local foo a                  b                  c
> >
> > . display strpos("`foo'", "  ")
> > 2
> >
> > . display `:length local foo'
> > 39
> >
> > If the spaces were trimmed, the length of `foo' would be 5.
> >
> > However, when I put this in a loop, I get different results:
> >
> > . forvalues i = 1/5 {
> >    2. local foo a                  b                  c
> >    3. }
> >
> > . display strpos("`foo'", "  ")
> > 0
> >
> > . display `:length local foo'
> > 5
> >
> > When you define `foo' outside of a loop, do you get a length of 5 or 39?
> >
> > Inside and outside of a loop, leading and trailing spaces are trimmed
> > unless double quotes are used, but as far as I can tell, internal
> > spaces are typically left untrimmed.
> >
> > Thank you,
> > Matt
> >
> > On Tue, Aug 20, 2013 at 3:05 PM, Nick Cox <njcoxstata@gmail.com> wrote:
> > > How many spaces are there between "1" and "2"?
> > >
> > > Without " " as delimiters, Stata trims internal spaces to single
> > > spaces in local macro definition. The " " insist on taking things
> > > quite literally.
> > >
> > > Try
> > >
> > > local foo a                  b                  c
> > >
> > > and see what happens.
> > >
> > > So, -strpos()- can't find a double space as there isn't one.
> > >
> > > I don't think looping is germane here.
> > >
> > > Nick
> > > njcoxstata@gmail.com
> > >
> > >
> > > On 20 August 2013 19:52, Matthew White <mwhite@poverty-action.org> wrote:
> > > > Hi all,
> > > >
> > > > Using Stata 13 for Windows 7, I'm trying to figure out an interaction
> > > > between -local- and loops. Normally when I define a local, multiple,
> > > > consecutive internal spaces are preserved. For example:
> > > >
> > > > . local x 1  2
> > > >
> > > > . display strpos("`x'", "  ")
> > > > 2
> > > >
> > > > Yet when I use the same definition in a loop, the internal spaces are trimmed:
> > > >
> > > > . forvalues i = 1/5 {
> > > >    2. local x 1  2
> > > >    3. }
> > > >
> > > > . display strpos("`x'", "  ")
> > > > 0
> > > >
> > > > Have others experienced this before? It's probably rare that this
> > > > would bite, but I'm running into such a situation now. Enclosing the
> > > > contents of the local by double quotes solves the problem:
> > > >
> > > > . forvalues i = 1/5 {
> > > >    2. local x "1  2"
> > > >    3. }
> > > >
> > > > . display strpos("`x'", "  ")
> > > > 2
> > > >
> > > > I'm just so used to dropping these quotes when I don't need them!
> > > >
> > > > Thank you,
> > > > Matt
> > > >
> > > > --
> > > > Matthew White
> > > > Senior Project Associate
> > > > Innovations for Poverty Action
> > > > 101 Whitney Avenue, New Haven, CT 06510 USA
> > > > www.poverty-action.org
> > > > *
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> >
> >
> > --
> > Matthew White
> > Senior Project Associate
> > Innovations for Poverty Action
> > 101 Whitney Avenue, New Haven, CT 06510 USA
> > www.poverty-action.org
> > *
> > *   For searches and help try:
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> *
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