Date:         Fri, 10 Dec 2004 21:57:43 -0500
Reply-To:     "Howard Schreier <hs AT dc-sug DOT org>" <nospam@HOWLES.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "Howard Schreier <hs AT dc-sug DOT org>" <nospam@HOWLES.COM>
Subject:      Re: Detect gaps and populate a variable

Here's my IF-less solution:

   data want;
   set have;
   by cnty_rte;
   retain gap;
   gap = sum(gap, begmp>lag(endmp) ) * (not first.cnty_rte);
   run;

On Mon, 6 Dec 2004 15:27:41 -0500, Mohamedshah, Yusuf
<Yusuf.Mohamedshah@FHWA.DOT.GOV> wrote:

>Dear all
>
>I have following dataset of State route-milepost system. What I want is to
write a code that can detect gaps for a given route and based on how many
gaps are for a given route, populate a variable indicating the number of
the gap.
>
>cnty_rte                        begmp           endmp
>
>0745609         0.01            0.6
>0745609         0.6             1.2
>0745609         1.6             2.5
>0745609         2.5             3.0
>0745609         3.0             4.5
>0745609         4.9             6.2
>0745609         6.2             9.8
>0745609         9.8             10.5
>0745609         10.5            11.5
>0745609         11.5            12.6
>0745610         0.0             3.6
>0745610         3.6             7.8
>0745610         9.2             10.1
>0745610         10.1            12.3
>....
>....
>
>
>What I want is the following output with a 'gap' variable coded as:
>
>cnty_rte                        begmp           endmp           gap
>
>0745609         0.01            0.6             0
>0745609         0.6             1.2             0
>0745609         1.6             2.5             1
>0745609         2.5             3.0             1
>0745609         3.0             4.5             1
>0745609         4.9             6.2             2
>0745609         6.2             9.8             2
>0745609         9.8             10.5            2
>0745609         10.5            11.5            2
>0745609         11.5            12.6            2
>0745610         0.0             3.6             0
>0745610         3.6             7.8             0
>0745610         9.2             10.1            1
>0745610         10.1            12.3            1
>....
>....
>
>So the 'gap' goes from 0 to 2 since there are two gaps in the first route.
And then it becomes zero because a route starts and goes from 0 to 1 since
there is only one gap.
>
>Any help would be appreciated.
>
>Thanks