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Re: st: loop until "0 real changes made"


From   Robert Picard <picard@netbox.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: loop until "0 real changes made"
Date   Mon, 29 Jul 2013 15:42:09 -0400

Perhaps an example will explain why...

* --------------- begin example ---------------------------
clear
set obs 1000000

set rms on

gen s = string(uniform(),"%21x")
clonevar s2 = s
gen s3 = s

gen `:type s' s4 = s

* --------------- end example -----------------------------



On Mon, Jul 29, 2013 at 3:34 PM, Sergiy Radyakin <serjradyakin@gmail.com> wrote:
> On Mon, Jul 29, 2013 at 3:19 PM, Robert Picard <picard@netbox.com> wrote:
>> Here's a more complete example of how to continue making substitutions
>> until there are no more changes. I'm with Nick on using -clonevar-
>> when making an exact copy of a variable, it is faster than -generate-
>
> Pardon my ignorance, but how is -clonevar- (implemented as an ado
> program) possibly faster than -generate- (built-in), if it is using
> -generate- inside and on top of that does some other things?? (like
> copying labels, formats, etc, which are not necessary for this
> exercise).
>
> From clonevar.ado ( 1.0.1  13oct2004):
> gen `type' `newvar' = `varname' `if' `in'
>
> Sergiy
>
> .
>> Also, avoid -regexr()- in Stata 13, it's slow as molasses.
>>
>> * --------------- begin example ---------------------------
>> clear
>> set obs 100000
>>
>> gen AD1 = string(uniform(),"%21x")
>> gen AD2 = string(uniform(),"%21x")
>> list in 1/5
>>
>> foreach v of var AD* {
>>         local more 1
>>         while `more' {
>>                 clonevar stemp = `v'
>>                 replace `v' = subinstr(`v',"0X-","X-",.)
>>                 count if `v' != stemp
>>                 local more = r(N)
>>                 drop stemp
>>         }
>> }
>> list in 1/5
>> * --------------- end example -----------------------------
>>
>>
>> On Mon, Jul 29, 2013 at 12:34 PM, Sergiy Radyakin
>> <serjradyakin@gmail.com> wrote:
>>> Nick's solution with two variables is the most generic approach that
>>> is useful in situations where it is difficult to predict if any
>>> changes are going to happen as a result of your code. It certainly is
>>> going to work here as well (I would only use a tempvar instead of AD2
>>> and generate instead of clonevar).
>>>
>>> However, why would you do this recoding to non-Turkish characters?
>>> Stata works with Turkish characters like with any other for which a
>>> corresponding ANSI page is available and proper font is installed:
>>>
>>> http://radyakin.org/statalist/2013072901/turkish.png
>>> http://radyakin.org/statalist/2013072901/turkish.do
>>>
>>> The ANSI page for Turkish is 1254. And I would try e.g.:
>>> replace `v'=regexr(`v', "`=char(196)'+`=char(158)'","`=char(208)'")
>>> instead of
>>> replace `v'=regexr(`v', "`=char(196)'+`=char(158)'","G")
>>>
>>>
>>> Best, Sergiy Radyakin
>>>
>>> On Mon, Jul 29, 2013 at 10:06 AM, Nick Cox <njcoxstata@gmail.com> wrote:
>>>> Plus the "+" if needed.
>>>> Nick
>>>> njcoxstata@gmail.com
>>>>
>>>>
>>>> On 29 July 2013 15:05, Nick Cox <njcoxstata@gmail.com> wrote:
>>>>> One answer is not to use regular expressions here at all. Use
>>>>> -subinstr()- with statements like
>>>>>
>>>>> replace `v' = subinstr(`v', "`=char(195)'`=char(135)'","C", .)
>>>>>
>>>>> Another answer is to set up a count of changes and stop when you hit zero.
>>>>>
>>>>> clonevar AD2 = AD
>>>>>
>>>>> foreach v of var AD {
>>>>>            replace AD2 = AD
>>>>>            <work with AD>
>>>>>            count if AD2 != AD
>>>>>            if r(N) == 0 continue, break
>>>>> }
>>>>>
>>>>> Nick
>>>>> njcoxstata@gmail.com
>>>>>
>>>>> On 29 July 2013 14:48, Haluk Vahaboglu <vahabo@hotmail.com> wrote:
>>>>>
>>>>>> I am using Stata 12.1 for Linux-64 bit and dealing with Turkish characters in string variables. I convert these Turkish characters (ı, ş, ü etc) to readable equivalents (i, s, u etc). Doing this with the code below:
>>>>>>
>>>>>> foreach v of var AD {
>>>>>>            replace `v'=regexr(`v', "`=char(195)'+`=char(135)'","C")
>>>>>>            replace `v'=regexr(`v', "`=char(196)'+`=char(176)'","I")
>>>>>>            replace `v'=regexr(`v', "`=char(195)'+`=char(167)'","c")
>>>>>>            replace `v'=regexr(`v', "`=char(195)'+`=char(182)'","o")
>>>>>>            replace `v'=regexr(`v', "`=char(196)'+`=char(177)'","i")
>>>>>>            replace `v'=regexr(`v', "`=char(196)'+`=char(158)'","G")
>>>>>>            replace `v'=regexr(`v', "`=char(196)'+`=char(159)'","g")
>>>>>>            replace `v'=regexr(`v', "`=char(195)'+`=char(156)'","U")
>>>>>>           replace `v'=regexr(`v', "`=char(195)'+`=char(188)'","u")
>>>>>>           replace `v'=regexr(`v', "`=char(197)'+`=char(158)'","S")
>>>>>>           replace `v'=regexr(`v', "`=char(195)'+`=char(150)'","O")
>>>>>>           replace `v'=regexr(`v', "`=char(197)'+`=char(159)'","s")
>>>>>> }
>>>>>>
>>>>>> However, this code cannot accomplish the conversion at the first time. Therefore, I have to do it 5 to 10 times to get a (0 real changes made) message.
>>>>>> My question is: can I make this loop run automatically until I get the (0 real changes made) message which indicates that all characters are converted.
>>>>
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>>>
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>>
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>
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