topic can i use array to drop some variables? in SAS Procedures

can i use array to drop some variables?

littlestone — Tue, 06 Sep 2011 18:51:02 GMT

consider following codes:

array TestVar

_Character_;

do i = 1 to 3;

drop TestVar;

end;

The purpose of this code is to drop the first three character variable. however, the code does not work for me. how should i edit the code to make it work?

can i use array to drop some variables?

art297 — Tue, 06 Sep 2011 19:00:28 GMT

You don't need the array. Aren't you just trying to do something like the following?:

data have;

input var 1 (x y z) ($);

cards;

1 1 2 3

2 5 2 1

3 4 3 4

;

data want;

set have;

drop _character_;

run;

Re: can i use array to drop some variables?

data_null__ — Tue, 06 Sep 2011 19:44:06 GMT

Drop is not executable. You will need to build the list first then use it in data step or data set option. Here is one way to do it.

25   proc transpose data=sashelp.heart(obs=0) out=vars;
26      var _char_;
27      run;
 
NOTE: There were 0 observations read from the data set SASHELP.HEART.
NOTE: The data set WORK.VARS has 7 observations and 2 variables.
NOTE: PROCEDURE TRANSPOSE used (Total process time):
      real time           0.01 seconds
      cpu time            0.01 seconds
 
 
28   proc sql noprint;
29      select _name_ into :drop3 separated by ' '
30         from vars(obs=3);
31      quit;
NOTE: PROCEDURE SQL used (Total process time):
      real time           0.00 seconds
      cpu time            0.00 seconds
 
 
32      run;
33   %put NOTE: DROP3=&drop3;
NOTE: DROP3=Status DeathCause Sex

can i use array to drop some variables?

littlestone — Tue, 06 Sep 2011 20:44:01 GMT

Thank you.

"drop _Character_" will drop ALL character variables. I am just wondering if there is some way that can selectively drop some character variables.

can i use array to drop some variables?

art297 — Tue, 06 Sep 2011 21:31:17 GMT

I'm not sure how selectively you want. From the pseudo code you had in your initial post, I presumed that it was all character variables.

If you want to drop a range of variables you can always do something like the following, i.e., use a variable list:

data have;

input var 1 (x y z extra) ($);

cards;

1 1 2 3 1

2 5 2 1 2

3 4 3 4 3

;

data want;

set have;

drop x--z;

run;

can i use array to drop some variables?

littlestone — Wed, 07 Sep 2011 01:24:47 GMT

thank you very much.

I will refrase my quetions: how to reorder variables to be in alphabetical order?

For example: supppose the original variables are (in order of):

C100 B100 A100 C99 B99 A99 C98 B98 A98 ...... C1 B1 A1

How can I change the order to:

A1 A2 ... A100 B1 B2 ... B100 C1 C2 .. C100

Reordering variables to be in alphabetical order

can i use array to drop some variables?

Ksharp — Wed, 07 Sep 2011 02:20:19 GMT

How about:

proc sql noprint;
 select name into : list separated by ' '
  from dictionary.columns 
   where libname='SASHELP' and memname='CLASS'
    order by name;
quit;
data class;
 retain &list;
 set sashelp.class;
run;

Ksharp

can i use array to drop some variables?

littlestone — Wed, 07 Sep 2011 03:07:12 GMT

thank you. I believe this is the answer i am looking for. but somehow i couldn't make it work:

data test;

input c2 b2 a2 c1 b1 a1;

cards;

1 2 3 4 5 6

;

proc sql noprint;

select name into : list separated by ' '

from dictionary.columns

where libname='work' and memname='test'

order by name;

quit;

data new;

retain &list;

set test;

run;

where am i wrong?

can i use array to drop some variables?

art297 — Wed, 07 Sep 2011 03:12:40 GMT

When you use one of the dictionary views in proc sql the libname and memname you specify both have to be in upper case. Thus your line should have read:

where libname='WORK' and memname='TEST'

However, it wouldn't have worked anyway, as the sort would not have been in the expected order and proc sql, as far as I know, doesn't allow numeric collation. Thus one extra step is needed, e.g.:

data have;

retain x1-x100 (100*1);

do i=1 to 2;output;end;

run;

proc sql noprint;

create table names as

select name

from dictionary.columns

where libname='WORK' and

memname='HAVE'

;

quit;

proc sort data=names sortseq=linguistic (numeric_collation=on);

by name;

run;

proc sql noprint;

select name into : list separated by ' '

from names

quit;

data class;

retain &list;

set sashelp.class;

run;

data want;

retain &list;

set have;

run;

can i use array to drop some variables?

littlestone — Wed, 07 Sep 2011 03:26:08 GMT

The code works now,

Thank you so much, art297 and Ksharp. I really learned a lot from both of you.