For SAS programmers, the PUT statement in the DATA step and the %PUT macro statement are useful statements that enable you to display the values of variables and macro variables, respectively. By default, the output appears in the SAS log. This article shares a few tips that help you to use these statements more effectively.
The PUT statement supports a "named output" syntax that enables you to easily display a variable name and value. The trick is to put an equal sign immediately after the name of a variable: PUT varname=; For example, the following statement displays the text "z wp_syntax">
data _null_; x = 9.1; y = 6; z = sqrt(x**2 + y**2); put z=; /* display variable and value */ run;
z=10.9
You can extend the previous tip to arrays and to sets of variables. The PUT statement enables you to display elements of an array (or multiple variables) by specifying the array name in parentheses, followed by an equal sign in parentheses, as follows:
data _null_; array x[5]; do k = 1 to dim(x); x[k] = k**2; end; put (x[*]) (=); /* put each element of array */ put (x1 x3 x5) (=); /* put each variable/value */ run;
x1=1 x2=4 x3=9 x4=16 x5=25 x1=1 x3=9 x5=25
This syntax is not supported for _TEMPORARY_ arrays. However, as a workaraound, you can use the CATQ function to concatenate array values into a character variable, as follows:
temp = catq('d', ',', of x[*]); /* x can be _TEMPORARY_ array */ put temp=;
Incidentally, if you ever want to apply a format to the values, the format name goes inside the second set of parentheses, after the equal sign: put (x1 x3 x5) (=6.2);
The previous tip displayed all values on a single line. Sometimes it is useful to display each value on its own line. To do that, put a slash after the equal sign, as follows:
. put (x[*]) (=/); /* put each element on separate lines */ .
x1=1 x2=4 x3=9 x4=16 x5=25
You can display all values of all variables by using the _ALL_ keyword, as follows:
data _null_; x = 9.1; y = 6; z = sqrt(x**2 + y**2); A = "SAS"; B = "Statistics"; put _ALL_; /* display all variables and values */ run;
x=9.1 y=6 z=10.9 A=SAS B=Statistics _ERROR_=0 _N_=1
Notice that in addition to the user-defined variables, the _ALL_ keyword also prints the values of two automatic variables named _ERROR_ and _N_.
Just as the PUT statement displays the value of an ordinary variable, you can use the %PUT statement to display the value of a macro variable. If you use the special "& wp_syntax">
SYSVLONG=9.04.01M4P110916
The results above are for my system, which is running SAS 9.4M4. Your SAS version might be different.
You can display the name and value of all user-defined macros by using the _USER_ keyword. You can display the values of all SAS automatic system macros by using the _AUTOMATIC_ keyword.
%let N = 50; %let NumSamples = 1e4; %put _USER_;
GLOBAL N 50 GLOBAL NUMSAMPLES 1e4
There you have it: six tips to make it easier to display the value of SAS variables and macro variables. Thanks to Jiangtang Hu who pointed out the %PUT &=var syntax in his blog in 2012. For additional features of the PUT and %PUT statements, see:
Rick Wicklin, PhD, is a distinguished researcher in computational statistics at SAS and is a principal developer of SAS/IML software. His areas of expertise include computational statistics, simulation, statistical graphics, and modern methods in statistical data analysis. Rick is author of the books Statistical Programming with SAS/IML Software and Simulating Data with SAS.
Thanks for the post and link to documentation. I learned about _READABLE_ and _WRITABLE_ and was reminded of &=
Quality post. Short, useful, and it serves as a reminder that no matter how many years you spend at it, there is always more to learn in a programming language. Cheers.
