Date: Mon, 9 Jul 2007 09:33:21 -0400
Reply-To: Muthia Kachirayan <muthia.kachirayan@GMAIL.COM>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: Muthia Kachirayan <muthia.kachirayan@GMAIL.COM>
Subject: Re: How to assign the 2nd obs value to the 1st obs
In-Reply-To: <BAY109-F281F2A8CC3089BAEC8EA0FB2070@phx.gbl>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Suhong,
The rule to generate IND_PEDIFF is not clear.
1. Do you want to ignore PR-PP grouping to get this IND_PEDIFF ?
2. Comparing the PE of 1st observation with the 2nd observation, we get 1
for contiguous and 0 for non-contiguous for first row. Similarly with 2nd
and 3rd for 2nd row .... (n-1)th and n-th for (n-1)th row. For the n-th row,
there will not be any comparison and how to fill for IND_PEDIFF ?
Please decide the rule.
There is no look-ahead SAS function similar to LAG(), but it is possible to
find a way for that functionality.
Regards,
Muthia Kachirayan
On 7/8/07, Suhong Tong <sophidt@hotmail.com> wrote:
>
> Hi Howard and Muthia,
>
> First, Thank you for helping me on my data problem. Second, I apologize
> that I provided a misleading output. Instead putting the wrong output I
> created, I really should have put a result that I want. Below is what I
> want:
>
> For the data presented below, PE=78765 - 78767, 94725 - 94728 are
> sequential
> numbers, thus these two sets are considered as counseling calls. I believe
> DIF(PE) only take care of 94726 - 94728,
> IFN( first.pr, 1....) can take care of PE=78765, but not something stuck
> in
> the middle(not the first.), like 94725, if I understood what you suggested
> correctly.
>
> I am thinking if SAS has some function can do things opposite to LAG
> function, meaning move 1 observation up, then my problem can be taken care
> of.
>
> Thanks,
>
> Sohpia
>
> pr pp pe IND_PEDIFF
> 26117 12644 78765 1
> 26117 12644 78766 1
> 26117 12644 78767 1
> 26117 12644 79398 0
> 26117 12644 80601 0
> 26117 12644 81343 0
> 26117 12644 81503 0
> 26117 12644 83429 0
> 32640 15436 107309 0
> 32640 15436 114404 0
> 32640 15436 163072 0
> 32640 15436 166924 0
> 32640 15436 94725 1
> 32640 15436 94726 1
> 32640 15436 94727 1
> 32640 15436 94728 1
>
>
>
> >From: "Howard Schreier <hs AT dc-sug DOT org>" <nospam@HOWLES.COM>
> >Reply-To: "Howard Schreier <hs AT dc-sug DOT org>" <nospam@HOWLES.COM>
> >To: SAS-L@LISTSERV.UGA.EDU
> >Subject: Re: How to assign the 2nd obs value to the 1st obs
> >Date: Sat, 7 Jul 2007 22:56:16 -0400
> >
> >On Fri, 6 Jul 2007 18:57:17 -0400, Sophia Tong <sophiDT@HOTMAIL.COM>
> wrote:
> >
> > >Dear list,
> > >
> > >I am trying to determine whether a call is a real counseling call or
> >random
> > >incoming call by looking at the PE numbers. If under the same PR-PP,
> PE
> > >come as a sequential numbers then that set of sequential numbers
> consider
> >as
> > >a set of counseling calls.
> > >
> > >What I did is let PE2=lag(PE), then PE_DIFF=PE-PE2, if PE_DIFF=1 then
> >that
> > >call identified as a conseling call. As you see below, the first obs
> with
> > >PE_DIFF=-264, this one should be identified as a real call. Another one
> > >where PE_DIFF=-72199, that one also should be identified as a real
> call.
> > >
> > >My question is how to assign 1s to IND_PEDIFF after SAS see the first
> 1s
> >in
> > >PE_DIFF?
> > >Mine way of flagging in IND_PEDIFF does not cover all the
> cases. Please
> >help.
> > >
> > >Thanks in advance.
> > >
> > >Sophia
> > > The SAS System 08:03
> > >Friday, July 6, 2007 30
> > >
> > >
> IND_
> > > PR PP PE PE2 PE_DIFF
> >PEDIFF
> > > CALLS
> > >
> > > 26117 12644 78765 79029 -264
> 1
> > > 1
> > > 26117 12644 78766 78765 1
> 1
> > > 2
> > > 26117 12644 78767 78766 1
> 1
> > > 3
> > > 26117 12644 79398 78767 631
> 0
> > > 4
> > > 26117 12644 80601 79398 1203
> 0
> > > 5
> > > 26117 12644 81343 80601 742
> 0
> > > 6
> > > 26117 12644 81503 81343 160
> 0
> > > 7
> > > 26117 12644 83429 81503 1926
> 0
> > > 8
> > > 32640 15436 107309 94633 12676
> 1
> > > 1
> > > 32640 15436 114404 107309 7095
> 0
> > > 2
> > > 32640 15436 163072 114404 48668
> 0
> > > 3
> > > 32640 15436 166924 163072 3852
> 0
> > > 4
> > > 32640 15436 94725 166924 -72199
> 0
> > > 5
> > > 32640 15436 94726 94725 1
> 1
> > > 6
> > > 32640 15436 94727 94726 1
> 1
> > > 7
> > > 32640 15436 94728 94727 1
> 1
> > > 8
> >
> >When presenting a table like this, it helps very much to reduce the
> >whitespace in order to avoid wrapping. See
> >
> >http://sascommunity.org/wiki/Preparing_Sample_Data_for_SAS-L
> >
> >Now, to the question. Try something like
> >
> > data result;
> > set given;
> > by pr pp;
> > IND_PEDIFF = ifn ( first.pr, 1, dif ( pe )=1 );
> > run;
> >
> >Notice that the indicator can be derived in one statement, with no
> >intermediate variables. The DIF function combines the roles of the LAG
> >function and the subtraction operator. When compared to the value 1, the
> >result is either true (1) or false (0). The IFN function overrides that
> >result for the first observation in each BY group.
>
> _________________________________________________________________
>
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