Macro: Check variable length, name, type of multiple tables with similar layout

/* set up list for the tables requied to scan for  the variables */

%let tlst = a b c d e f g;

/* Method 1: use parameter */

/* Generate vairable list for each table */

%macro varlen (sec=);
%let i = 1;
%do %while (%scan(&sec., &i, ‘ ‘) ne );
%let tbl= %scan(&sec., &i, ‘ ‘);
proc contents data = section&tbl._ug out=ug&tbl. (keep= MEMNAME name type length) noprint;
proc contents data = section&tbl._gr out=gr&tbl. (keep= MEMNAME name type length) noprint;
%let i = %eval (&i +1);
%end;
run;
%mend varlen;
%varlen (sec = &tlst.);

/* Method 2: use macro variable list directly */

/* Append varaible lists to one table */
%macro comp ;
%let i = 1;
%do %while (%scan(&tlst., &i, ‘ ‘) ne );
%let tbl= %scan(&tlst., &i, ‘ ‘);
proc append base = uglen  data = ug&tbl.;
run;
%let i = %eval (&i +1);
%end;
%let i = 1;
%do %while (%scan(&tlst., &i, ‘ ‘) ne );
%let tbl= %scan(&tlst., &i, ‘ ‘);
proc append base = grlen  data = gr&tbl.;
run;
%let i = %eval (&i +1);
%end;
proc sort data = uglen;
by name memname;
proc sort data = grlen;
by name memname;
run;
%mend comp;
%comp ;

SAS: Convert Variable between Numeric and Character Format

A. Use Put or Input
Convert between numeric and character variable.

• character to numeric (input)

old_char = "2018";
new_num = input(old_char, 8.);
new_num = 2018;

• character to numeric (input) to character (put)

old_char = "2018";
new_char = put (input (substr(old_char , 1, 4 ), 8.) -1 , 4.);
new_char = "2017";

/* or */
new_char = put (old_char*1-1 , 4.);
new_char = "2017";

• numeric to character (put), and with leading Zero.

old_num = 2018;
new_char = put(old_num, 4.); *new_char = "2018";
new_char1 = put(old_num, z8.); *new_char1 = "00002018";

• numeric to character (put) to numeric (input)

old_num = 2018;
new_num = input(substr(put(old_num, 4.),3, 2) , 8.);
new_num = 18;

Use the following functions to check whether any digit or alphabetic character is in the character variable. The results will be the position of the first digit/alphabetic character in the field.

check1 = anydigit(var); *return position of first digit, 0 if not found in the string;
check2 = anyalpha(var); *return position of first alphabetic character, 0 if not found in the string;
check3 = notalpha(var); *return position of first non digit, 0 if not found in the string;
check4 = notdigit(var); *return position of first non alphabetic character, 0 if not found in the string;

• Please note there should be no space in between % and statement eg. macro, let, mend, put, eval etc.
• To apply the macro variable, use &varname. format.

CODE:

%macro setyr;
%let yr = 14;
%let nextyr =%eval(&yr. +1);  /* 15 */
%let next2yr=%eval(&yr. +2);  /* 16 */
%let fisyr = “20%substr(&yr., 1,2)/%substr(&nextyr., 1,2)”;   /* “2014/2015” */
%let fisnextyr = “20%substr(&nextyr., 1,2)/%substr(&next2yr., 1, 2)”;   /* “2015/2016” */
%let year = “20&yr.”; /* “2014” */
%put &yr;
%put &nextyr;
%put &next2yr;
%put &fisyr;
%put &fisnextyr;
%put &year;
%mend setyr;
%setyr;

OUTPUT:
14
15
16
“2014/15”
“2015/16”
“2014”

B. Use Vvalue fuction
Vvalue() returns the formatted value that is associate with the variable.

data want;
data have;
new_charvar1 = vvalue(formatted_numvar1);  *formatted means the variable has been applied with format;
new_numvar2= vvalue(formated_charvar2);
run;

SAS: Variables/Fields with same Prefix

I have a SAS file that stores students course selection (up to 20 fields) and grades for each course (up to 20 fields) for a certain semester. To set the sas working file, I use the follow data step. Both course variables and grades variables have the common prefix “crs” and “grade”.  It is more efficient to list the 20 course variables using “crs1-crs20” than list each and every one of them.

%let varlist = crs1-crs20 grade1-grade20 studentid major;

Data tem1;

Set  coursefile_fw16 (keep = &varlist.);

run;