SAS - count number of colums with array

sas_count_number_of_columns_with_array.md

Say you have a dataset. You wish to find out the number of character columns, numerical columns, and total columns.

One way to do this is to use the SAS array in conjunction with dim() function.

I've created the following code demo to illustrate this - inspired by this SAS blog forum.

data all_chars;
	var1 = "hello";
	var2 = "world";
run;

data all_numerics;
	var1 = 1;
	var2 = 2;
run;

data mixed_types;
	var1 = 1;
	var2 = "hello";
run;

%macro count_columns(inData);
	data outData (keep=numeric_columns char_columns total_columns);
		set &inData. (obs=1);  /* your dataset */
		array nums(*) _numeric_ ;
		array chrs(*) _character_ ;
		if _n_=1 then do;
			numeric_columns = dim(nums);
			char_columns = dim(chrs);
			total_columns = numeric_columns + char_columns;
			output;
		end;
	run;

	data _null_;
		set outData;
		put "inData: &inData.";
		put numeric_columns=;
		put char_columns=;
		put total_columns=;
	run;
%mend;

%count_columns(all_chars);
%count_columns(all_numerics);
%count_columns(mixed_types);

Output:

...

inData: all_chars
numeric_columns=0
char_columns=2
total_columns=2

...

inData: all_numerics
numeric_columns=2
char_columns=0
total_columns=2

...

inData: mixed_types
numeric_columns=1
char_columns=1
total_columns=2

...

There are many ways to do this. This is one of them.