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Re: st: how to count the number of certain characters in a string variable?


From   Tirthankar Chakravarty <tirthankar.chakravarty@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: how to count the number of certain characters in a string variable?
Date   Tue, 28 Jul 2009 15:16:53 +0100

<>

Using the -msub()- function in Nick Cox's -egenmore- package (SSC),
here is an example that counts the number of crosses in the variable
"crosses" and creates a new variable which replaces them with "a"s in
the variable "replaced". You can tweak this if you would like to only
replace the "aa"s.
********************
clear*
set obs 100
g crosses = " "
local cross "x"
forv i=1/ 100 {
	qui: replace crosses="`cross'" in `i'
	local cross "`cross'x"
}
// ssc install egemore, replace
egen noccur = noccur(crosses), string("x")
su noccur
egen replaced = msub(crosses), find("x") replace("a")
********************

T

2009/7/28  <gjhxmu@sina.com>:
> Dear statalists,
>
> I have a string variable X as follows:
>
> X                Y
>
> aabb            2
>
> bbdd            0
>
> cdba            1
>
> dxbaa          2
>
> dxaa            2
>
> I want to generate a variable Y to stand for the number of certain characters,
> such as "aa" and replace these characters with other characters, such as "zz".
>
>
> How to do it ?
>
> Thank you !
>
> Sincerely,
>
> From Rose.
>
>
> *
> *   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/
>



-- 
To every ω-consistent recursive class κ of formulae there correspond
recursive class signs r, such that neither v Gen r nor Neg(v Gen r)
belongs to Flg(κ) (where v is the free variable of r).

*
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