For "yes" and "no", read also "true" and "false" (or "not true").
One further reference is
What is true and false in Stata?
http://www.stata.com/support/faqs/data/trueorfalse.html
Nick
[email protected]
Roger Newson replied to Paul O'Brien:
> >The help on -index- leaves me a bit ignorant.
> >
> >I use this without knowing how it works:
> >
> >gen oral = "OVYS" if index(stk,"OVYS")
> >replace oral = "MICROG" if index(stk, "MICROG")
> >replace oral ="FEMOD" if index(stk, "FEMOD")
> >replace oral = "LOGED" if index(stk, "LOGED")
> >
> >Index 'returns the position' it finds the string'
> >
> >The position of MICROG could be, say, 9th character to 14th in the
> >string and returns 9-14. How is this translated in a yes?
>
> The -index()- function evaluates to zero if the second
> argument appears
> nowhere in the first argument. And -if- treats zero value as
> "no", and
> treats all nonzero numeric values (including negative and
> missing values)
> as "yes". See -help ifcmd- and -help if- for further references.
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
