topic deleting variables in order in SAS Procedures

deleting variables in order

R_A_G_ — Wed, 22 Feb 2012 17:40:07 GMT

Hello SAS experts,

I have a huge dataset that need to delete variables for example 2-20 and need to know how.

Thanks

Re: deleting variables in order

Haikuo — Wed, 22 Feb 2012 17:44:19 GMT

Hi,

Check out 'drop' or 'keep' statements or options.

data want;

set sashelp.class;

drop sex--weight;

run;

Regards,

Haikuo

deleting variables in order

art297 — Wed, 22 Feb 2012 17:45:59 GMT

Take a look at datanull's suggested method at: http://communities.sas.com/message/38407#38407

deleting variables in order

R_A_G_ — Wed, 22 Feb 2012 17:46:43 GMT

this is a dataset with 500 variables, It would be very hard to do this one by one, I need to drop let say variables 10 through variable 20. I have droped the ones with same prefix but there are more to drop.

thanks

deleting variables in order

Haikuo — Wed, 22 Feb 2012 17:48:36 GMT

if they are in order like you said, you can use '--' to do the job. just edit my post.

deleting variables in order

R_A_G_ — Wed, 22 Feb 2012 17:49:43 GMT

Thanks Art, but this looks a lot more complicated than it should be. Is there any simple code for droping sequntial variables?

thanks

deleting variables in order

art297 — Wed, 22 Feb 2012 17:58:38 GMT

The method is easier than it appears. Here is an example dropping variable 2 thru 3 from sashelp.class:

proc sql noprint;

select name

into :vlist separated by " "

from dictionary.columns

where libname eq 'SASHELP' and

memname = "CLASS" and

varnum between 2 and 3

;

quit;

data want;

set sashelp.class (drop=&vlist.);

run;

deleting variables in order

Tom — Wed, 22 Feb 2012 18:06:51 GMT

I am not sure what is easier than using a variable name range list as suggested above. Read the documentation:

http://support.sas.com/documentation/cdl/en/lrcon/62955/HTML/default/viewer.htm#a000695105.htm

Using name range lists (such as sex -- weight) is dangerous enough without being able drop variables by position without even knowing the variables names.

deleting variables in order

R_A_G_ — Wed, 22 Feb 2012 18:14:21 GMT

I've never worked with SQL syntax, so I actually do not know what any of these lines mean. Is there any other way to do this

Thank you

deleting variables in order

art297 — Wed, 22 Feb 2012 18:19:31 GMT

While I agree with Tom that it is dangerous to drop variable by number, the only lines that have to be changed in the proc sql code are:

where libname eq 'SASHELP' and

SASHELP has to be changed to the library where your data is located, but typed in UPPER CASE

memname = "CLASS" and

CLASS has to be changed to the name of your data file, but typed in UPPER CASE

varnum between 2 and 3

and, where I used 2 and 3 in the above statement, if you wanted to drop variables 10 thru 20 you would replace that line with:

varnum between 10 and 20

deleting variables in order

Astounding — Wed, 22 Feb 2012 19:08:40 GMT

It sounds like you would be more comfortable with a low-tech approach. If that's true ...

Run a PROC CONTENTS on the data set, adding the POSITION option. That way, you can see a list of all variables in order. You will more easily be able to select ranges of variables to remove, and apply that using the syntax that has already been shown here:

data new;

set old (drop=first_variable_to_drop -- last_variable_to_drop first_variable_in_another_range -- last_variable_in_another_range);

run;

You'll need to know the names of the first and last variable being dropped.

deleting variables in order

Tom — Wed, 22 Feb 2012 19:18:31 GMT

Or even lower tech just open the dataset or proc print it and you will see the variables in order.

deleting variables in order

R_A_G_ — Wed, 22 Feb 2012 23:51:54 GMT

Thank you All,

Low tech sounds great to me.

Thanks

deleting variables in order

Mit — Thu, 23 Feb 2012 01:24:59 GMT

If you are worried about the order of the variables then how about trying this:

%let varlist1= ;*Define your variable list in the order you would like to keep;

%let varlist2= ; * Define you variables that you would like to drop;

data a;

set dsin;

drop &varlist2;

run;

Data dsout;

retail &varlist1;

set a;

run;