Date:         Sun, 27 Jun 2004 14:39:32 -0400
Reply-To:     Jim Groeneveld <jim.groeneveld@VITATRON.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Jim Groeneveld <jim.groeneveld@VITATRON.COM>
Subject:      Re: Trick for Mass Renaming of Variables
Comments: To: Kevin Myers <KevinMyers@AUSTIN.RR.COM>

Hi Kevin,

Just a few (*untested*) suggestions:

1. get a list of current names in a dataset
a. from PROC CONTENTS DATA=... OUT=... (KEEP=Name),
b. or PROC DATASETS,
c. or via SQL
d. or SASHELP.

2.a. write an ascii file via FILE with lines of type: 'oldname = newname'
     and %INCLUDE that file later after the RENAME keyword in PROC
     DATASETS (don't forget the double semicolon).
2.b. make macro variable list of old names and one of new names using:
     NameList = /* initialize empty */;
     CALL EXECUTE ('%LET NameList = &NameLIST ' || Name || ';');
     from a data step. In PROC DATASETS do something like:
     RENAME
     %LET NR = 1;
     %LET OldName = %SCAN (%NameList, ^Nr, %STR( ));
/*   %LET NewName = %SCAN (%NameList, ^Nr, %STR( )); */
     %DO %WHILE (&OldName NE AND &NewName NE);
        &OldName = &NewName /* &NewName may be COL&Nr */
     %END;
     ; /* semicolon ends RENAME */
2.c. or build the whole PROC DATASETS call from the data step reading
     the names, thus IF _N_ EQ 1 THEN build the who part intil the RENAME
     and the first oldname = newname specification. only that specification
     for the remaining variable names and adding the closing code after the
     last one.

I assume you know methods to specify a constant character prefix (COL) and
a variable numeric postfix, e.g. using an incremental macro variable.

There may be numerous other ways to do it, maybe even quicker, more
efficient, maybe all within SQL.

BTW, doesn't RENAME _CHARACTER_ _NUMERIC_ = .............. help?

Regards - Jim (via the web interface).

On Sun, 27 Jun 2004 10:33:32 -0500, Kevin Myers <KevinMyers@AUSTIN.RR.COM>
wrote:

>Hello,
>
>I'm looking for something simple and elegant that will allow all variables
>of a data set to be renamed to a list of generic names with a given prefix
>and a numeric suffix, e.g. if there are 100 variables in the data set and
>the prefix is "col" then the variables should be renamed col1-col100.
>Conceptually what I want to do is something similar to the following data
>step pseudo-code:
>
>rename _all_=col1-col100;
>
>However, there are several problems with that:
>
>1.  Using a data step requires all of the data to be read and re-written,
>when all that should be necessary is to modify the data set's variable
>descriptor info.
>
>2. The variable list _all_ includes automatic variables that aren't
actually
>part of the data set variables that need to be changed, such as _N_.
>
>Alternatively, I could use PROC TRANSPOSE to transpose the data then
>transpose it back (using appropriate parameters and statements for the
>proc), which would have the desired effect but would be extremely slow, and
>would required reading and re-writing the data multiple times.
>
>I have considered (started to write) a macro for this purpose using PROC
SQL
>to get a list of column names and then to loop over that list generating
>RENAME statements for PROC DATASETS.  I'm confident that I can get that
>approach to work fairly quickly, but it seems like there ought to be a
>simpler way...  BTW, PROC DATASETS doesn't seem to allow variable list
>syntax in its RENAME statement.
>
>Can anyone think of a simpler approach?
>
>Thanks,
>s/KAM