Date: Wed, 23 Oct 1996 00:00:22 -0700
Reply-To: Karsten Self <kmself@IX.NETCOM.COM>
Sender: "SAS(r) Discussion" <SAS-L@UGA.CC.UGA.EDU>
From: Karsten Self <kmself@IX.NETCOM.COM>
Subject: Re: Look Ahead Methodology: 99% Working!
Gerry, intersting post. I'm replying blind (from home, no SAS, no manuals),
Ian will probably do his thing and correct my mistakes.
Misquoting from memory, there are several conditions which cause a SAS data
step to stop executing, including reaching EOF on a raw data file. This is
documented in the DATA STEP portion of the "SAS Language, Reference" manual,
titled something like "stopping/halting the DATA step".
I believe that what is happening is your LASTREC infile option (and label)
are being triggered on what you intend to be the *next to last* record -- an
off-by-one error. If this is the case, then the following describes the
situation:
You intend:
SAS reads the next-to-last record, checks next record for remainder of JOURNAL
field. Data step returns for one final pass, on which the LASTREC
condition is
triggered.
SAS does:
Reads next-to-last record. Checks next (final) record for remainder of
JOURNAL.
Finds EOF. Executes LASTREC label.
Cures (several possible):
Put your last-record processing on the LASTREC label -- input and output the
final record. Make sure that the remainder of your processing is consistent
with proper processing of the n-1th record. I would insert some diagnostic
code (PUT statements with data values and data step loop (_N_) value) in the
LASTREC label code block to test this. You might also try running your code
through the DATA Step debugger for a small data set.
I believe there may be an "ignore eof" type option on infile, though I don't
know of the top of my head what it is. You'd probably have to substitute
your own halting logic if you used it, to prevent some rather nasty SAS errors.
BTW & FWIW -- very clear post & a good presentation of your problem. And
the tylenol is right next to the JD.
============================================================================
Original post
============================================================================
Date: Mon, 21 Oct 1996 17:21:26 EDT
From: Gerry <STATMAN@PACEVM.DAC.PACE.EDU>
Subject: Look Ahead Methodology: 99% Working !
The Task
********
The problem is that for some of the records, the first field, named
JOURNAL, is folded across two or more lines. For example:
<...>
The solution requires the program to "look ahead" to the next record to
see if the first position is filled, indicating a record where JOURNAL
is on one line, or blank, indicating that the JOURNAL field is folded
across 2 or more lines.
<...>
The program attached below almost works, except that it will not output
the last record in the file. According to the SASLOG, all of the records
in the file are read in properly.
<...>
I'm sure I must be overlooking something obvious, or that I missed in
the manual, but for the life of me, I can't find it and its driving
me crazy !
<...>
I apologize for the length of this note, but when asking for help, I
think it is better to provide too much information than not enough.
Any and all help will be gratefully appreciated -- now where's that
bottle of tylenol !
Gerard T. Pauline |
Pace University | Phone: (212) 346-1706
Dept of Academic Computing | Internet: Gerry @ Pace.Edu
1 Pace Plaza, Office Y-25 | Bitnet: Gerry @ Pacevm
New York, NY 10038 | Web: http://www.pace.edu/acadcomp
-------------------------------- Program -------------------------------
Filename INPDATA 'LIBRARY DATABASE A1' ;
Options LS=95 NODATE ;
Data LIBRARY (Keep=JOURNAL RECORD) ;
Infile INPDATA Eof=LASTREC ;
Length JOURNAL $ 200
RECORD $ 41 ;
Array JTXT {5} $ 38 _Temporary_ ;
Array RTXT {5} $ 41 _Temporary_ ;
I = 1 ; /* Initialize Array Index */
JTXT{2} = '' ; /* Blank Out Array Elements From Previous */
JTXT{3} = '' ; /* Record, Element 1 Is Always Populated */
JTXT{4} = '' ; /* In Each Array */
JTXT{5} = '' ;
RTXT{2} = '' ;
RTXT{3} = '' ;
RTXT{4} = '' ;
RTXT{5} = '' ;
Do While (1) ;
/*--- Read In Current Record, "Look Ahead" To The Next Record ---*/
Input @1 JTXT{I} $Char38. @40 RTXT{I} $Char41. /
@1 RCHK1 $1. @40 RCHK2 $Char41. @@ ;
If ((RCHK1 = ' ') |
((RCHK1 ^= ' ') & (Compress(RCHK2) = ''))) Then
Do ; /* Journal Field Is "Folded" */
I + 1 ; /* Increment The Array Subscript */
Continue ; /* Populate The Next JTXT Element */
End ;
Else
Leave ; /* Journal Field Is All On One Line */
End ; /* End DO WHILE (1) Loop */
/*--- Form The JOURNAL & RECORD Variables, And Output To Dataset ---*/
JOURNAL = Trim(JTXT{1}) || ' ' || Trim(JTXT{2}) || ' ' ||
Trim(JTXT{3}) || ' ' || Trim(JTXT{4}) || ' ' ||
Trim(JTXT{5}) ;
RECORD = RTXT{1} ;
Output LIBRARY ;
Return ; /* Not At E-O-F Yet */
LASTREC: Output LIBRARY ; /* Account For The Last (?) Record ... */
/* At Least I Thought I Was ! */
Return ;
Run ;
----------------------------------------
Karsten Self / kmself@ix.netcom.com
What part of gestalt don't you understand?
