Re: st: if command

["Danielle H.Ferry" <dferry@gc.cuny.edu>]

Hmm, actually, perhaps I should have been more clear on what I am doing 
here. I am not actually using the values of the variable <aRate> in 
these statements. The basic idea is I want to run essentially the same 
procedure several times on different variables. There are style-type 
things I want to change depending on what that variable is (i.e. title 
on graph), so I write conditions to differentiate between the relevant 
variable. So, a snipped version of my program would look like this:

program test

...

if `1'==aRate {
	local title = "Abortion rate"
}

if `1'==bRate {
	local title = "Birth rate"
}

...

end

The argument `1' is either aRate or bRate.

Danielle Ferry

On Feb 12, 2004, at 5:02 PM, David Kantor wrote:


> At 03:26 PM 2/12/2004 -0500, Danielle Ferry wrote:
>
> > Can anyone please explain when the if command requires quotes around 
> > the expression and when it does not?
> >
> > For example, I've found the following seemingly quirky behavior:
> >
> > 1) if "`1'"=="aRate" | "`1'"=="bRate" | "`1'"=="pRate" --> requires 
> > quotes
> > 2) if `1'==aRate --> does not require quotes
> > 3) if "`1'"=="apRatio" --> requires quotes
> As far as I know, if you are comparing to a string constant, you need 
> quotes.
>
> Example 2 probably ought to have quotes if it is meant to test a 
> string value.  It would, however, pass as a legitimate expression 
> if...
>  aRate happens to be a variable name and...
>    it is numeric and so is `1'  (that is the contents of the local 1), 
> or
>    it is string, and `1' contains enclosing quotes (I haven't tried 
> this), or
>    it is either numeric or string, and `i' is also a variable name of 
> a compatible type.
> But in these cases, you are implicitly testing observation 1, which 
> you might not have intended.
>
> Example 2 would also pass if aRate is a scalar and `1' is numeric (and 
> if `1' is a variable name, then you are testing observation 1).
>
> In any case, while Example 2 might sometimes pass, it is probably not 
> doing what you intended.
>
> I hope this helps.
> -- David
>
> David Kantor
> Institute for Policy Studies
> Johns Hopkins University
> dkantor@jhu.edu
> 410-516-5404
>
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