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/* assume that you have assign
a path into a macro variable called "path," and you
have a dataset called "finaloutput," which uses consecutive numbers as temporary
ID, such as temp1-tempx, and a dataset called listitem,
which contains the real itemids.*/ /* obtain the item list and put the last
item on top of the list */
data listitem;
set
listitem;
position = _N_;
proc
sort;
by
descending
position; run;
/* assign the position of the last item as a global macro variable */
data listitem;
set
listitem;
/* use the following syntax if SAS version 9 is used. Symputx
can trim the extra space in the macro variable*/
if _N_ =
1
call symputx("lastitem",
position); run;
/* use the following syntax if SAS version 8 or below is used.
Extra space will remain in the macro*/
if _N_ =
1
call symput("last",
position); run;
/* If symput is used, a macro trim function is needed to remove extra space,
otherwise, skip this step*/
%LET lastitem=%trim(&last);
/* To verify the macro variables are assigned, show all user-defined macro
variables on the output window. If symput is used, you will see something like
"last 30" and "lastitem 30." */
%put _user_;
/* transpose the list of itemid so that it is listed horizontally. By default
the field names of the itemid are COL1-COLx */
proc
transpose
data=listitem
out=listitem2;
var
itemid; run;
/* If the itemids start with a number, the following step is necessary.
It will add a letter "Q" to every itemid to make it legal in SAS variable
assignment. */
data listitem2;
set
listitem2;
length newitemid1-newitemid&last
$15.
col1-col&last $15.;
array col(&last) $ col1-col&last;
array newitemid(&last) $
newitemid1-newitemid&last;
do i=
1
to
&last;
newitemid(i) = "Q"||col(i);
end ;
run ;
/* output the new itemlist as a text file. If the real IDs do not start with
a number, the preceding step is not necessary and you
can write the output statement as "put col1 - col&last"
*/
data itemid2;
set
itemid2;
FILE
"&path\newitemlist.txt"
lrecl=35000;
put
newitemid1 - newitem&last;
run ;
/* define the last position of the text file. In this case, each itemid has 5
digitals plus the letter "Q" (5+1=6). */
%LET lastpos=%eval(&lastitem
* 6 + &lastitem - 1);
/* read the itemid list from text file back to SAS as a long string, and then
put the string
into a macro variable */
data itemlist3;
infile
"&path\newitemlist.txt"
lrecl=35000;
input itemidlist $1
- &lastpos;
call symput("itemidlist",
itemidlist);
run ;
/* replace the old itemid list with the new list */
data finaloutput;
set
finaloutput;
array temp(&last)
tempid1-tempid$last;
array newitemid(&last) &itemidlist;
do i =
1
to
&last;
newitemid(i) = temp(i);
end ;
drop temp1-temp&last i;
run ;
quit ;
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