Re: st: levelsof

[Keith Dear <keith.dear@anu.edu.au>]

Luhang,
Read -help levelsof-. You need to name, as an option, the local macro 
where you want the list to be stored, thus:
        levelsof YY, loc(levels)
where "levels" is your choice of name for a local macro.

Alternatively, you can access the result of -levelsof- as r(levels), like this:
        use Y, clear
        levelsof YY
        use X, clear
        foreach l in `=r(levels)' {
           replace XX=subinstr(XX,"`l'","",.)
        }
Note that foreach needs "in" not "of" in this usage, because there is 
no keyword (such as "local"), simply a list of terms. In your 
example, `=r(levels)' evaluates to the list `"a"' `"b"'.
kd

At 01:17 PM 21/09/2007, you wrote:

> Dear all,
>
> I'm trying to take some strings out of a string variable. Suppose data
> set Y contains the list of strings, named variable YY, that I want to
> take out from a string variable XX in data set X. An example is that
> YY takes value "a" and "b", and XX takes "ac" and "bd", the results I
> want are "c" and "d".
>
> My code is as following:
>
> ***************************************************
> use Y,clear
> levelsof YY
>
> use X,clear
> foreach l of local levels {
>            replace XX=subinstr(XX,"`l'","",.)
> }
>
> **************************************************
> It doesn't work. Could someone tell me what is wrong with my code? Or
> is there better method achieving this? Many thanks in advance.
>
> Cheers,
> Luhang
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Dr Keith B.G. Dear
Senior Fellow in Biostatistics
National Centre for Epidemiology and Population Health
Australian National University
Canberra, ACT 0200, Australia
Tel: 02 612 54865, Fax: 02 612 50740
http://nceph.anu.edu.au/Staff_Students/staff_pages/dear.php
CRICOS provider #00120C

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