Moreover, we learn components of sas macro code and some benefits of. Combining multiple sas files using a macro with the set. Macros and parallel processing sas support communities. The % macro statement can appear anywhere in a sas program, except within data lines. The macro processor resumes processing the compiled macro instructions. Formats and translating sas dates since sas keeps track of dates and times and datetimes as numbers relative to some. May 01, 2019 sas macro provides an incredible way to make a process easy and automatic. Ods pdf textsfont times roman,12pt,boldsimple macro using age. This workshop will introduce the user to a few of the.
Sas macro provides an incredible way to make a process easy and automatic. If used properly, it can make programming easier and more fun. You want to extract transaction details, manpower details, budget details and others for current month only and this is monthly task repetitive. An easy way to run thousands of regressions in sas the. The footnotes macro can be called any time valid expense values should. Sas statistical analysis system is one of the most popular software for data analysis. This macro will generate and run sas code for each sequence specified in the do loop in step 2 and for each geography specified in the %callst macro. This course will also cover the use of autocall libraries, data step function calls and. The iterative do processes statements a specified number of times. Furthermore, we can use it to write sas programs that are dynamic and flexible.
Most of the time, this is very convenient, but any time you avoid. Matches the preceding character 0 or more times matches the preceding character 1 or more times matches the preceding character 0. At times the word scanner waits for the macro processor to perform an activity, such as. This seminar is designed to introduce the basics of sas macro language. The macro processor triggers the word scanner to resume tokenization. Ods pdf textsfont times roman,12pt,boldsimple macro using. Fraeman, evidera, bethesda, md abstract a propensity score is the probability that an individual will be assigned to a condition or group, given a set of. This paper presents several methods for repeatedly calling a macro and gives the advantages and disadvantages of each. Here, we will see different sas macro variables, functions of macro in sas programming language. Setting aside the macro language, can you describe how you would do this parallel processing in eg without any macro code. First, we developed a fundamental macro called %cdiscdtm to convert all the datestimes into iso 8601 format.
The values of a date variable represent the number of days before or after january 1, 1960, and the values of a time variable is the number of seconds since midnight. Sas programs and macro processing 4 how sas processes statements without macro activity 11 number digits, date values, time values, and hexadecimal numbers. Name a string of characters beginning with an underscore or letter. Most programmers know that the most efficient way to analyze one model across many subsets of the data perhaps each country or each state is to sort the data and use a by statement to repeat the analysis for each unique value of one or more categorical variables. This statement creates a macro variable named macvar and. However, not every program is improved by using macros. For information about how sas processes statements with macro activity, see getting started with the macro facility in sas macro language. Then, they are available for data step processing but sas does not add them to the output data set as they are temporary in nature. You can refer to a macro variable as many times as you need to in a sas program. It can never return a value, though in some cases you can mimic functions. Even though your client eg is running on windows and your sas session is linux, you can still use %include. This paper is designed for people who know the basics of sas programming, but know nothing about sas macro programming. The creation of dynamic code based on data values and the set up of generic, reusable code libraries will be discussed. See the sas macro manual for the syntax of the call.
Cohen astrazeneca lp abstract the sas macro language is another language that rests on top of regular sas code. Macros as they apply to sasconnect, sasstat, sasgraph and other modules of sas will be taught. The general form a %let statement is %let macrovariablename value. Common examples are terminating a program when some condition is met or capturing the runtime value of a. A macro definition cannot contain a cards statement, a datalines statement, a parmcards statement, or data lines. If want to do same action for several datastepsprocs, macro approach may be easier sas array references cannot be used as. Most programmers know that the most efficient way to analyze one model across many subsets of the data perhaps each country or each state is to sort the data and use a by statement to repeat the analysis for each unique value of one or more categorical. Index changes each time the loop executes based on the. When sas compiles program text, two delimiters trigger macro processor activity. Methods for repeated macro calls sas proceedings and more. The execution time is the time that it takes sas to execute the data step for each observation in a sas file. For a more extensive list and more detailed information, see the sas guide to macro processing on the shelf in my cubicle.
This statement should be written ouside of the macro block. The present paper introduces a macro that simplifies the process, significantly reduces the amount of coding and programming skills needed thus reducing the likelihood of producing the wrong result, runs up to 50 or more times faster than the multiple proc transpose. It is often used to reduce the amount of regular sas code and it facilitates passing information from one. It is provided to help you understand what is going on behind the scenes. Jul 18, 2012 why bygroup processing is fast and macro processing is slow. Novikov mentions that the macro approach minimizes disk space, but that the bygroup technique minimizes time. A sas macro returns text that is inserted into the processing stream. In sas, dates and times are considered numeric variables, but they have several special properties to be aware of. The relationship contains a pattern of simple repetitive actions.
Moreover, we learn components of sas macro code and some benefits of sas macro. Writing cleaner and more powerful sas code using macros myweb. Reference, and sas programs and macro processing in sas macro language. Dates, times, and date times are commonly used variable types in research. Using macros to automate sas processing sas support. Basic macros rely on symbolic substitution to place values in particular locations in sas codethey simply create code. But, while macros certainly can be challenging, it is also true that the basic concepts are not difficult to learn. It is often used to reduce the amount of regular sas code and it facilitates passing information from one procedure to another procedure. Some of the macro character functions that have analogous data step functions. It is intended to provide an intuitive understanding of macro and sas code processing. This type of macro function provides information about the string it takes as argument see following example.
If, however, you had 200 sas data files, say file1 file2 file200 then this would be alot of typing doing the set statement for 200 files. The rest of the macros were then developed to allow for dynamic processing when creating as well as using cdisc compliant data sets. Sas interview questions, base sas, macros, proc sql, proc datasets, rename modify kill save update merge interleave statistical analysis system, sas, sas notes, sas training, sas programming, sas program, sas log analysis, log sas, sas interleave, interleave statement in sas, sas retain, retain statement in sas, sas put statement, put statement in sas, sas merge statement, merge statement in. Dec 05, 2019 at times the word scanner waits for the macro processor to perform an activity, such as searching the symbol tables or compiling a macro definition. For example, this program refers to macro variable dsn twice. A common question on sas discussion forums is how to repeat an analysis multiple times. In plain english except for the obvious sas code the program would be. In sas, dates and times are considered numeric variables, but they have several special properties to. These actions begin when text is submitted to the input stack and the word scanner begins tokenization. Special any character or group of characters that have special meaning to the sas system, for example sas operators. The use of macro variables and macro code is difficult to learn without some training. Macro statements and macro variables are resolved at compilation time and have no bearing on the time it takes to execute the data step. Its default working whenever we run the macro application. If the macro processor generates text during its activity, then it pauses while the word scanner tokenizes the text and sends the tokens to the appropriate target.
It is widely used for various purposes such as data management, data mining, report writing, statistical analysis, business modeling, applications development and data warehousing. Sas has many macro statements which are inbuilt in the sas programming language. Sas functions byten returns one character in the ascii or ebcdic collating sequence where n is an integer representing a specific ascii or ebcdic character. Our macro first modifies the input data set appropriately and then applies sass standard cox regression procedure, proc phreg, using weights and countingprocess style of specifying survival times to the modified data set. In a complicated program with many referenced to a particular parameter value, date range. Apr 27, 2019 variables to identify the first and last observations in a group. This macro will give information about the whole 0003 sequence, not just table b01001. The first time the %do group iterates, macrovariable is equal to start. A macro definition must precede the invocation of that macro in your code.
A macro program for repeating a procedure multiple times. Similarly, a sas datetime variable contains both date and time information e. The lesson here is to check your dates before and after processing. In this seminar we will cover the following topics. Automating the process of determining the number of times a macro needs to be utilized for a task is just one of the several applications of macro variable arrays. An introduction to sas macros steven first, systems. As an input to a macro parameter in a format, label, drop, keep, length or output statement sas arrays refer to variables or constants not datasets or the value of a variable use. Do the following data step replacing xy with 10, then do it again replacing xy with 20, then do it again replacing x. For laboratory, vital signs, and ecg data, this macro can generate tables having descriptive statistics for change from baseline. For a more formal and detailed explanation, see the chapters sas programs and macro processing and macro processing in the sas 9. The sas macro language is a very versatile and useful tool. You can change the value of the index variable during processing. The first published description of this technique that i know of is the article a remark on efficient simulations in sas by ilya novikov 2003, j. I need a macro to repeat a data step for several datasets whose names are identical except for 2 characters.
Fraeman, evidera, bethesda, md abstract a propensity score is the probability that an individual will be assigned to a condition or group, given a set of covariates when the assignment is made. It recognizes the end of the %do group at the %end instructin and proceeds to %mend. The previous sections illustrate the relationship between macro compilation and execution and data step compilation and execution. Create sas macro variables that contain values from rows in a querys result x x. Macro to generate summary and descriptive statistics tables. They are used by other sas programs without explicitly declaring them. We present a new sas macro %pshreg that can be used to fit a proportional subdistribution hazards model for survival data subject to competing risks. Dec 05, 2019 specify integers or macro expressions that generate integers to control the number of times the portion of the macro between the iterative %do and %end statements is processed. You should take the program courses in the order listed in the chart below, which shows when and in what format courses are offered. Common examples are terminating a program when some condition is met or capturing the runtime value of a variable in the program log. The example in this section shows you how the macro processor creates and resolves a macro variable. An easy way to run thousands of regressions in sas the do loop. At the time of execution what we now have is to execute just the compiled code i.
Using mlogic to see macro processing in log file option mlogic. Sas macros for faster data manipulation complete tutorial. The sas par macro ellen hertzmark, handan wand, and donna spiegelman march 8, 2012 abstract what % of the cases would be prevented if it were possible to eliminate one or more risk factors from a target population. Macro programming is generally considered an advanced topic. This handson workshop shows how to use the sas macro facility to automate a. An introduction to sas macros steven first, systems seminar consultants, madison, wi abstract the sas programming language has a rich toolbox of features that can offer a lot of power to the user. Why bygroup processing is fast and macro processing is slow. Variables to identify the first and last observations in a group. An easier and faster way to untranspose a wide file. Associates a format, informat, label, andor length with one or more variables cards or cards4 datalines or datalines4 indicates that data lines follow suffix of 4 if data has. We explain how the macro processor works, and how to. This macro is very powerful in processing partial, invalid and missing date values. The sas macro facility is useful for defining sas statements that need to be executed repeatedly, but the best method of implementing repeated macro calls depends on the circumstances. Using lexical expansion the macro call incr a,b,areg can lead to the generation of a moveaddmove instruction sequence to increment a by the value of b using areg to perform the arithmetic.
Sas has several procedures that generate reports, but only the put statement within a data step gives complete. For most macro programming, you do not need this level of detail. My main concern here is how to return a value from a macro. Selects observations from a sas data set that meet certain conditions before sas brings them into the data or proc step for processing. Standard sas macros for standard datetime processing. Array processing jordan elm introduction most mathematical and computer languages have some notation for repeating.
The compilation time is the time that it takes the sas compiler to scan the sas source code and convert it to an executable program. How sas processes statements with macro activity in a program with macro activity, the macro processor can generate text that is placed on the input stack to be tokenized by the word scanner. Sas macro, including macro arrays, and build to more complex examples. It dispalys a warning message in log window whenever macrocall is not resolved. Sas dates are simply stored as the number of days from january 1, 1960, and so the twodigit vs. Creating sas data sets sas data files or sas views x x create indexes on tables x creating sas data sets from input files that contain raw data external files x analyzing, manipulating, or presenting your data x x listing reports writing external files to disk or tape x computing the values for new variables x x retrieving system. Proc sql using sas, sas macro programming, and output delivery system ods and data visualization essentials using sas quarter 4 winter or summer. Macro options can be changed by using option statement. This will print the already resolved macro variable from. In practice inside of the loop the macro are created, but i dont know how to call them when i need outside. An introduction to sas macros 10 the sas macro language a second sas programming language for string manipulation. Im going to quibble with dirk here in an important way.
674 1115 537 1046 1507 606 615 609 441 854 167 1173 740 1031 578 603 1032 646 933 30 417 621 42 284 1297 1482 823 244 336 893 366 1079 769 1050 752 296 1281 1184 169 539 609 1204 967 479 1410