SAS/Programming

SAS Programming Modes SAS uses a variety of programming modes to manipulate data. Among them are : Global statements, which define or alter the program environment SAS data steps, which use the data step language to create, input, modify, and output data in rectangular database tables (datasets). A SAS datastep commences with the DATA keyword, and is generally terminated with a RUN statement. Procedures, which are pre compiled structures designed to produce defined outcomes given (usually) the input of SAS datasets and one or more control parameters A SAS procedure commences with the PROC keyword followed by the procedure name, and is generally terminated with a RUN or QUIT statement. SQL statements, issued within PROC SQL, that provide an alternative (and more standard) method of creating and modifying database tables IML (Interactive Matrix Language) statements, issued within PROC IML, that provide a method of manipulating matrix data. SAS Graph statements, which use a special vocabulary of statements to control graphical output. ODS statements, which use another special vocabulary of statements to control output to external media The SAS Macro Language, which modifies program statements prior to execution, and allows generic code to be adapted for use each time it is run, by substitution of control parameters. Macro code is generally identified by statements which contain keywords prefaced by % or &. Macros A simple example The following macro computes frequencies, plots them and store the graph in a file. Instead of repeating all those steps each time, you just need one line to perform all these tasks together. %macro plot_dist(var=,title=,name=); proc freq data = lib.fic_dad_06_1 ; table &var /out = _freq_ ; run ; goptions reset=all; filename output &name; goptions device=png gsfname=output gsfmode=replace; proc gplot data = _freq_ (where = (&var > 1 & &var < 70)) ; title &title ; symbol v = circle c = black i = none; plot count * &var / grid href=10 20 50 ; run; quit ; %mend ; %plot_dist(var = EFFECTIF , title = "Effectif", name = "W:/…/hist_eff.png"); The declaration of a macro begins with %macro and ends with %mend. Arguments in the macro are preceded by the & symbol.