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Jack,
I call it "Boolean normalizing operator" because it turns any true value
(i.e. anything not zero and not missing) to 1 and any false value (i.e.
anything zero or missing) to 0. As _Null_ pointer out, same as mnemonic NOT
NOT. Hence the following, where X is a numeric expression,
bool = ^^ X ;
bool = not not X ;
are fully equivalent to
if X = 0 or missing (X) then bool = 0 ;
else bool = 1 ;
or
if X then bool = 1 ; else bool = 0 ;
Another clever trick from the same bag is
bool = X = -X ;
It comes with a slight marring side effect. I will leave it to SAS-L to
ponder which condition it tests for and what the side effect is. When, a
long time ago, I showed it to Bob Virgile (renowned for his deep
appreciatiion of such SAS artifacts) he called it "cute".
Kind regards
------------
Paul Dorfman
Jax, FL
------------
On Tue, 13 Oct 2009 07:40:52 -0400, Jack Clark <jclark@HILLTOP.UMBC.EDU>
wrote:
>Paul,
>
>Will you explain the double caret operator from your solution below? I
>see that it is returning a 1 or 0 instead of the position in the string
>normally returned by INDEXW, but I am not familiar with the operator.
>
>Thank you,
>
>Jack
>
>
>
>
>Jack Clark
>Senior Research Analyst
>phone: 410-455-6256
>fax: 410-455-6850
>jclark@hilltop.umbc.edu
>
>University of Maryland, Baltimore County
>Sondheim Hall, 3rd Floor
>1000 Hilltop Circle
>Baltimore, MD 21250
>
>
>
>
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>From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of
>Paul Dorfman
>Sent: Tuesday, October 13, 2009 1:41 AM
>To: SAS-L@LISTSERV.UGA.EDU
>Subject: Re: Determining if a character string includes a phrase
>
>Kevin,
>
>Frankly, I fail to see why it seems to be difficult. Both INDEXw and
>FINDx
>functions are suited for the task, e.g.:
>
>data _null_ ;
> input text $64. ;
> text = translate (text, " ", ".,") ;
> array pp $ 64 p1-p3 ("the train", "the station", "and i wasn't on
>it") ;
> array phrase [3] ;
> do over pp ;
> phrase[_i_] = ^^ indexw (upcase (text), upcase (strip (pp))) ;
> end ;
> put phrase[*] ;
> cards ;
>The train left the station, and I wasn't on it.
>I wasn't on it when the train left the station.
>The station was empty: the train had left without me.
>;
>run ;
>
>A much more interesting and involved question would be what is the most
>efficient way to confirm or reject the presence or the phrase
>
>"the Raven still sitting above my door, his eyes all dreaming"
>
>in
>
>"And the Raven, never flitting, still is sitting, still is sitting on
>the
>pallid bust of Pallas just above my chamber door, and his eyes have all
>the
>seeming of the demon that is dreaming".
>
>Any takers?
>
>Kind regards
>------------
>Paul Dorfman
>Jax, FL
>------------
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