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Re: st: local and loops
From
Jeph Herrin <[email protected]>
To
[email protected]
Subject
Re: st: local and loops
Date
Tue, 20 Aug 2013 15:34:48 -0400
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
[email protected]
On 20 August 2013 20:17, Matthew White <[email protected]> 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 <[email protected]> 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
[email protected]
On 20 August 2013 19:52, Matthew White <[email protected]> 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
*
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*
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* http://www.stata.com/support/faqs/resources/statalist-faq/
* http://www.ats.ucla.edu/stat/stata/