keep variables when their names meet some condition

[jkim197]

Hello all.

I have a simple question for base sas programming.

I want to delete variables if their name meet some condition.

For example

I have variables port1_1, port1_2, port1_3, port2_1, port2_2, port2_3, port3_1, port3_2, port3_3

I want to delete port1_1, port2_2, port3_3

I made a list of variable name to delete in separate dataset, but I don't know how to use them...

What I have is two datasets

have1 and have2

<have1>

family	stock	port1_1	port1_2	port1_3	port1_4	port2_1	port2_2	port2_3	port2_4	port3_1	port3_2	port3_3	port3_4	port4_1	port4_2	port4_3	port4_4
1	1	1	0	1	.	0	0	0	.	1	0	1	.	.	.	.	.
1	2	1	1	0	.	1	1	0	.	0	0	0	.	.	.	.	.
1	3	1	0	1	.	0	0	0	.	1	0	1	.	.	.	.	.
1	4	1	1	1	.	1	1	1	.	1	1	1	.	.	.	.	.
1	5	0	0	0	.	0	1	1	.	0	1	1	.	.	.	.	.
1	6	1	1	1	.	1	1	1	.	1	1	1	.	.	.	.	.
1	7	0	0	0	.	0	1	0	.	0	0	0	.	.	.	.	.
1	9	0	0	0	.	0	1	0	.	0	0	0	.	.	.	.	.
1	11	1	0	0	.	0	0	0	.	0	0	0	.	.	.	.	.
1	12	1	1	1	.	1	1	1	.	1	1	1	.	.	.	.	.
1	13	1	1	1	.	1	1	1	.	1	1	1	.	.	.	.	.
1	15	1	1	0	.	1	1	0	.	0	0	0	.	.	.	.	.
1	16	0	0	0	.	0	1	0	.	0	0	0	.	.	.	.	.
1	17	1	1	0	.	1	1	0	.	0	0	0	.	.	.	.	.
1	18	1	1	0	.	1	1	0	.	0	0	0	.	.	.	.	.
1	19	0	0	0	.	0	1	0	.	0	0	0	.	.	.	.	.
1	21	1	1	0	.	1	1	0	.	0	0	0	.	.	.	.	.
1	23	1	0	0	.	0	0	0	.	0	0	0	.	.	.	.	.
1	24	1	0	0	.	0	0	0	.	0	0	0	.	.	.	.	.
2	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
2	2	1	1	0	1	1	1	0	1	0	0	0	0	1	1	0	1
2	3	1	1	0	1	1	1	0	1	0	0	0	0	1	1	0	1
2	4	1	1	0	1	1	1	0	1	0	0	0	0	1	1	0	1
2	5	1	1	0	1	1	1	0	1	0	0	0	0	1	1	0	1
2	6	1	0	0	1	0	0	0	0	0	0	0	0	1	0	0	1
2	7	1	1	1	0	1	1	1	0	1	1	1	0	0	0	0	0
2	8	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
2	9	0	0	0	0	0	1	1	0	0	1	1	0	0	0	0	0
2	11	0	0	0	0	0	1	1	0	0	1	1	0	0	0	0	0
2	12	0	0	0	0	0	0	0	0	0	0	1	0	0	0	0	0
2	27	0	0	0	0	0	0	0	0	0	0	1	1	0	0	1	1
2	28	0	0	0	0	0	0	0	0	0	0	1	1	0	0	1	1
2	29	0	0	0	0	0	0	0	0	0	0	1	1	0	0	1	1

<have2> --> they are the variables that I want to delete

Variable Name

port1_1

port2_2

port3_3

port4_4

how do I efficiently delete them??

[Kurt_Bremser]

Use proc sql to create a list for dropping:

proc sql noprint;
select name into :deletelist separated by ' ' from have2;
quit;

data want;
set have;
drop &deletelist;
run;

With suitable conditions, you can pull such lists directly from dictionary.columns.

[Astounding]

@Kurt_Bremser has the right idea.  In part, the answer depends on what you mean by "efficient".  To get his answer to run  a little bit faster, change the final step to:

data want;
set have (drop=&deletelist);
run;