Date: Thu, 29 Mar 2001 15:43:15 +0100
Reply-To: Peter Crawford <peter.crawford@DB.COM>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: Peter Crawford <peter.crawford@DB.COM>
Subject: Datastep looping
Content-type: text/plain; charset=iso-8859-1
Hi Don
The EOF switch is not evaluated until the first INPUT statement.
So your code never satisfies the test in the first line generated by the macro.
I think the "looping" condition occurs because you have input in a step which
cannot read from it, because you issue a delete if _n_=1;
Here is result of my test, using SET with end=eof. It generates the same looping message
558 data test ;
559 put eof= ;
560 if _n_ > 1 then DELETE ;
561 set end=eof;
562 put eof= ;
563 run ;
eof=0
eof=1
eof=1
NOTE: DATA STEP stopped due to looping.
NOTE: There were 1 observations read fro
NOTE: The data set WORK.TEST has 1 obser
NOTE: The DATA statement used 0.01 CPU s
564 data test ;
565 put eof= ;
566 set end=eof;
567 if _n_ > 1 then DELETE ;
568 put eof= ;
569 run ;
eof=0
eof=1
eof=1
NOTE: There were 1 observations read fro
NOTE: The data set WORK.TEST has 1 obser
NOTE: The DATA statement used 0.01 CPU s
I think the condition is a data step loop which has a set statement (or merge or input ?)
but which does not execute that statement in the current iteration.
The same "looping" message surfaces in v6.12
Somewhere in SAS-L archives, this question must have been investigated.
Regards
Peter Crawford
Datum: 29/03/2001 05:41
An: SAS-L@listserv.uga.edu
Antwort an: Don_Stanley@bnz.co.nz
Betreff: Datastep looping
Nachrichtentext:
Maybe I'm in brain switched off mode today ...
Given this TEST file on MVS V609E TS470
********************************* Top of Data **********************************
TEST
******************************** Bottom of Data ********************************
why does this code
49 options mprint ;
50 data test ;
51 infile testcase end=eof ;
52
53 %p_hdr(eofvar=EOF,eofonly=Y) ;
MPRINT(P_HDR): IF EOF AND _N_ EQ 1 THEN DO ;
MPRINT(P_HDR): PUT 'NO DATA IN THE INPUT FILE' ;
MPRINT(P_HDR): ABORT ABEND 999 ;
MPRINT(P_HDR): END ;
MPRINT(P_HDR): IF _N_ EQ 1 THEN DELETE ;
3 The SAS System
54 input @1 ; put _infile_ ;
55 run ;
NOTE: The infile TESTCASE is:
Dsname=IS413.D30920.FORMATS(TESTCASE),
Unit=3390,Volume=M2P02D,Disp=SHR,Blksize=80,
Lrecl=80,Recfm=FB
NOTE: DATA STEP stopped due to looping.
NOTE: 0 records were read from the infile TESTCASE.
NOTE: The data set WORK.TEST has 0 observations and 0 variables.
NOTE: The DATA statement used 0.02 CPU seconds and 5049K.
issue the looping message? I would have expected it to do the delete when _n_=1,
and since it hasn't read a record yet, to read the single record when _n_=2. The
debugger seems to imply that the code stops after the DELETE when _n_ = 1, no
obvious signs of looping.
The DELETE isn't necessary, I'm changing the macro that generates this to stop
it appearing, but I'm curious why the datastep thinks its looping.
Any ideas?
Thanks
Don
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