Examples will include functions like %sysevalf and %sysfunc. Click on every function name in the table to read in more details with example. A character operand was found in the %eval function or %if condition where a numeric operand is required. Macro quoting functions, other special character masking tools. When we are done, you will know the difference between a macro, a macro variable, a macro statement, and a macro function. When we submit our program, sas will process the macro variables first. Using the index function with macro variables in a.
Operands in arithmetic or logical expressions are always text. The sas data step function substr commonly pronounced sub string function is used to work with a specific position or positions of characters within a. By default, the macro processor uses integer arithmetic, and only integers and hexadecimal values that represent integers can be converted to a numeric value. Therefore, using it with a numeric variable would have given you unpredictable results. Macro functions include character functions, evaluation functions, and quoting functions. In this paper, we will walk through the various types of functions, macros, and how the functions and macros are stored and processed internally.
The informat will tell sas on how to read data into sas variables. Sas date variable by placing the informat in the input statement. The findw function searches each substring for the keyword. In macros, we can write functions inside or outside of the macroblock global function a % length. Similarly, functions and macros can also be developed by user based on his needs and requirements. In the original design of the sas system, the data and proc steps performed useful work, and the macro language. Defensive programming using sas macros suave, november 25th, 2014 chris clausen senior programmer analyst university of victoria.
This tutorial covers most frequently used sas character functions with examples. The companion function to the input function is the put function. The %upcase and %qupcase functions convert lowercase characters in the argument to uppercase. The function being used requires a certain number of arguments and that number has been exceeded, for example,%substrabcd,1,2,3. However, an operand that represents a number can be temporarily converted to a numeric value when an expression is evaluated. Abstract the macro facility is an important feature of the sas language. Sas macros the following four sas macros logreg, combine, rocplot and yindex macros show how we fitted the logistic regression model, manipulated the data table and prepared the roc dataset, generated roc curve, and generated youdens index table for plot gradually. Scan, substr, trim, catx, index, tranwrd, find, sum. Custom useful sas functions using the proc fcmp procedure. May 01, 2019 today we discuss sas macros for beginners and how sas macro makes our life easier by reducing the redundancy or repetitiveness of a code. Compbl function it compresses multiple blanks to a single blank. If the value is truncated or the variable is not defined on the operating environment, %sysget displays a warning message in the log.
The following datasets found in the sashelp library are used in this article for various examples. This function can be a sas function, a function written with sastoolkit software, or a function created using the fcmp procedure in base sas procedures guide. If a special character or mnemonic affects the way the macro processor constructs macro program statements, you must mask the item during macro compilation or during the compilation of a macro program statement in open code by using either the %str or %nrstr macro quoting functions. It also helps create dynamic variables within the code that can take different values for different run instances of the same code. Macro functions operate much as regular sas functions,except that the arguments are within the context of the macro language. The substr function takes a character matrix as an argument along with starting positions and lengths and produces a character matrix with the same dimensions as the argument. Since it is a data step, use the substr function, not %substr. When you use the substr function on the left side of an assignment statement, sas places the value of argument with the expression on right side. When the beginning of step is found, all statements in the step are compiled. Again, think of what a put statement doesit takes a sas value character or numeric, applies a format and writes out the result, usually to a file. The true heroes of macro debugging kevin russell and russ tyndall, sas institute inc. Macro variables are character variables so the %eval function may be required. Taking substring from the name of the variable macro sas. What common data step and macro messages are trying to tell you.
The %substr function will pick out a subcomponent of a string variable. We will introduce interaction between macros and regular sas language, offer tips on debugging macros, and discuss sas macro options. The function being used requires a certain number of arguments and that number has been exceeded, for example,% substr abcd,1,2,3. Since it is a data step, use the substr function, not % substr. Macro functions are especially useful as programming tools, because the function call is replaced directly by the result. The macro language functions are listed in the following table. Getting the in operator to function inside a sas macro. Input charstr,informat convert character string to numeric. The program is scanned one statement at a time looking for the beginning of step step boundary.
Macros can also be declared for blocks of code which will be. In the this section we will show some examples of these different types of functions. The fundamentals of macro quoting functions pharmasug. Numbers are stored in such as way as to make it impossible to go to position 7 or position 4 of the number only character strings have fixed positions. In addition to the %scan and %qscan pairs, there are many macro functions and autocall macros that have q. Many of the examples and some of the text in this paper are based on sections in. Macros from beginning to mend a simple and practical approach to the sas macro facility michael g.
The %sysget function returns the value as a character string. The differences are in how they are used and applied. Calculate average height and store in a macro variable. The purpose of using the macro language is used to generate sas codes based on our instruction.
The %substr and %qsubstr functions produce a substring of argument, beginning at position, for length number of characters. You can use all macro functions in both macro definitions and open code. Its a little bit tricky to deal character strings as compared to numeric values. If the macro variable consists of the text you want to extract then quote it, otherwise leave the macro variable unquoted. In general, a macro language function processes one or more arguments and produces a result. This macro contains the macro calls for all the macros discussed in the above steps to execute them in a sequential order. Produces a substring and masks special characters and mnemonic operators.
Sas macros for computing the mediated effect in the pretestposttest control group design david mackinnon keywords. Before executing this macro all the macros discussed in steps 1 through 4 should be compiled. Anyone who struggles with developing sas macros in order to extend the power and ease of use of the sas system should be aware of the myriad data step and scl functions that the sysfunc facility makes available. Input anzacday yymmdd10 the sas system will automatically convert the text representation of the raw data variable in to a sas date variable with a value of 629, the number of days between 1 january 1960 and 25 april 1997 example 2. The put function takes a sas value the first argument and writes out the formatted result using format supplied as the. I have multiple programs in a project, and the final programs will reference this macro global to identify if there is an exception, and depending on the either the select.
Elements of the result matrix are substrings of the corresponding argument elements. Hence, it is required to know the practical usage of character functions. If you omit length, sas extracts the remainder of the expression. Using the index function with macro variables in a macro loop posted 11202014 2356 views in reply to dmoovendhan also the variables flag and var1 will get initialised only when the condition satisfies. Finally, macros can help us create interactive systems in the absence of sasaf. Details in a data step, if the substr right of function returns a value to a variable that has not previously been assigned a length, then that variable is given the length of the first argument. The %sysevalf function evaluates arithmetic and logical expressions using floatingpoint arithmetic and returns a value that is formatted using the best32. Extraction and use of text strings with sas when source exceeds. Sas macro provides an incredible way to make a process easy and automatic. Sas macros sas macro is used to automate the repetitive tasks i. Macros could only contain macro statements, as they had to resolve their return value.
Today we discuss sas macros for beginners and how sas macro makes our life easier by reducing the redundancy or repetitiveness of a code. Generating receiver operating characteristic roc curve. Carpenter, california occidental consultants abstract many macro functions are very analogous to those of the data step. System macros are useful you can %bquote me on that. Dec 05, 2019 the %index function searches source for the first occurrence of string and returns the position of its first character. See substr right of function in sas functions and call routines. Now macros can wear the clothes of a proc fcmp function, this function. Its syntax is similar to the mid function in many other programming languages, specifying the variable name, start position and length of the substring. Hi, you can use the substr function to extract the part of the string. Macros are resolved prior to the compilation and execution of the sas code. Back in the older versions of sas there was a fair bit of functionality that was missing, and macro conviniently filled in there. Mastering this facility will enable the novice user to become an accomplished programmer.
Finally, macros can help us create interactive systems in the absence of sas af. Because %str masks parentheses without a match, the macro processor does not recognize the arguments of a function or the parameter values of a macro invocation. Getting the in operator to function inside a sas macro perry watts, independent consultant, elkins park, pa abstract large sas macros with many parameters require that user values be checked at run time. Sas tutorial for beginners to advanced practical guide. Sasbuddy presenting first ever free mobile app on sas concepts. While data step functions are applied to values on the program data vector, pdv, macro functions are used to create, modify, and work with text strings. The % substr and %qsubstr functions produce a substring of argument, beginning at position, for length number of characters. The paper first explores key concepts and syntaxes of perl regular expressions prx and then describes the ways to use them in sas macros by taking advantage of the prx functions and call routines built in the data step via %sysfunc function and %syscall.
As tom has pointed out, knowing base sas as well as possible is the best route to minimising code. However, without debugging options, it is almost impossible to locate and correct all the errors in an application. The sas substr function a beginners tutorial paul d. Languages which use a mid function also have a left and a right function, to extract the leftmost. For example, a data step will be compiled and executed, then a procedure step will be compiled and executed important. Argument 2 to macro function % substr is not a number. The % substr function can handle only three arguments. Using this function, we can report length of the macrovariable. To use this feature, set both the mfile and mprint system options on and also assign mprint as the fileref for the file to contain the output generated by the macro facility.
Quoting functions allow the user to pass macro arguments while. The sas language provides a substr function for snipping a piece of a character variable. This function is assigned an i18n level 2 status and designed for use with sbcs, dbcs, and mbcs utf8. One convenient checking tool is the in operator that has been extended in 9. Here, we will see different sas macro variables, functions of macro in sas programming language. Oct 18, 2010 the substr function is meant to work with character strings or character variables.
Sas is rich in various builtin functions, and predefined sas supplied macros. The compilation of sas programs sas code is compiled and executed alternately in steps. In addition a number of autocall macros, such as %left, %trim, and %verify, are also supplied that act like macro functions. For a description of quoting in sas macro language, see macro quoting. An introduction to sas macros 6 flow without macros without macros, sas programs are data and proc steps.
Using the same logic as the substr function, since the length of rep is determined in the compile stage and since the number of repetitions could vary. Hi everyone i have to program a macro function that receive a parameter and return an attribute found in a table. A character operand was found in the %eval function or. The % substr function will pick out a subcomponent of a string variable. You can use the value returned by %sysget as a condition for determining further action to take or parts of a sas program to execute. Some common examples are syntax errors during macro compilation or. For more information, see internationalization compatibility. Sas has a powerful programming feature called macros which allows us to avoid repetitive sections of code and to use them again and again when needed. The %substr function can handle only three arguments. When using macros in sas, statements and commands are created as needed by. The sas macro language includes a number of macro functions, such as %upcase, %qscan, and %substr. Below are some frequentely used and important string functions in sas.
The goal of this paper is to get you started with using this facility in sas macros. Sas informats are used to read, or input data from external files known as flat files ascii files, text files or sequential files. Userdefined variables can be assigned in several ways. Printing the statements generated during macro execution to a file is useful for debugging macros when you want to test generated text in a later sas session. Data step or case proc sql statement, create an exception tier. Then, have a look at the blog post of sas training in delhi to gather additional knowledge. Substr replaces n characters starting at the character you specify in position. Sas macros are designed to generate output and data sets, not values. A macro language function processes one or more arguments and produces a result. In this case, we are giving flexibility to users to provide information of input dataset name, the analysis variable and output dataset and the macro returns the mean value of the analysis variable in the output dataset. Subrstr str,start,length sample replace selected postion by substr with string given at right side of operator.
Carpenters complete guide to the sas macro language, third. It includes useful tips and tricks of sas macro programming and outlines real world examples of automation with sas macros. Ensure that the required number of arguments are met and not exceeded. Sas evaluates the expression in an if statement to produce a result that. The macro language functions are listed in macro functions. This function will be called inline in other programs such a proc sql or datastep this is the program i made libname qdata c. Writing cleaner and more powerful sas code using macros.
90 533 1589 1068 1057 227 773 799 438 567 1048 251 137 931 393 122 980 1082 1150 422 79 1107 211 58 306 118 1464 1195 15 1012 771 936 454 1437 652 1224 574