JC Raymond, Education, SAS Bill Fehlner, Education, SAS

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Programming Techniques in SAS Using the Macro
Facility
Programming Techniques in SAS Using the Macro
Facility















































JC Raymond, Education, SAS
Bill Fehlner, Education, SAS 514
395-4087 jc.raymond_at_sas.com 416
307-4513 bill.fehlner_at_sas.com
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(No Transcript)
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Programming Examples

1. Reuse dynamic code
2. Automated Process
3. Automate job control
4. Extend SQL with custom functions
5. Pure macros without data steps
6. The Factorial
7. Divide and Conquer

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Some Macro Building Blocks

• Macro programs with parameters
• Macro Variables stored in Symbol tables
• Automatic variables, e.g. System return codes
• Run-time functions, e.g. the resolve function.
• Macro Functions
• Recursive programming

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1. Reuse Dynamic Code
demo1_dynamicAutoexec.sas
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1. Reuse Dynamic Code
The Greeting Macro
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1. Reuse Dynamic Code
The Greeting Macro

• sysuserid contains the userid of the SAS session
  
• Keyword parameters have a default value.
• A macro statement begins a macro definition and
  a mend statement ends it.
• put statements write to the SAS log.

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1. Reuse Dynamic Code
Macro Variable Dictionary
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1. Reuse Dynamic Code
Macro Variable Dictionary
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1. Reuse Dynamic Code
Delete Variables
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2. Automated Process
Final report
Process parameters
Sas data sets
Proc tabulate
Create sample data
Sas data set
Task 2
Task 2
Task 1 obs1
Task 1
Task 1
Data step reads log
Sas log
Route log file to disk
Task 2 obs1
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2. Automated Process
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2. Automated Process
Using The Benchmark Macro
demo2_runBenchmark.sas
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2. Automated Process
The Benchmark Macro
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2. Automated Process
Take-aways

• local insures no interference with variables
  potentially existing outside of the macro
  procedure.
• A macro program can check for a null parameter.

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2. Automated Process
The Benchmark Macro
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2. Automated Process
Take-aways

• include allows blocks of code to be stored in
  text files and inserted into the program code at
  any time.
• scan can be used to split a parameter value into
  multiple units.
• Title statements (and any others) can be dynamic
  in the macro world.

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2. Automated Process
The Benchmark Macro
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2. Automated Process
Take-aways

• Proc Printto can route the SAS log to a text
  file.
• Multiple ampersand expressions select one macro
  variable from a named group of macro variables.

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3. Automated Job Control
demo3_demostrateJobControl.sas
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3. Automated Job Control
The Jobcontrol Macro
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3. Automated Job Control
Take-aways

• The parmbuff option permits a variable number of
  parameters in a macro call.
• scan can be used to select a parameter from the
  parameter string stored in the syspbuff macro.
• syspbuff contains the entire parameter string.
  The str((,)) specifies that a right
  parenthesis, a comma, and a left parenthesis are
  delimiters for the scan.
• eval( ) function permits integer arithmetic in a
  macro expression.

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4. Extend SQL
demo4_surrogateKeys.sas
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4. Extend SQL
The Nextval Macro
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4. Extend SQL
Take-aways

• Macro parameters can be passed by reference.
  In this case constantName contains a reference to
  a macro variable
• constantName inserts the name of the target
  macro variable.
• constantName inserts the value of the target
  macro variable.
• constantName appearing outside of a macro
  statement supplies the return value for the
  nextval macro program.

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4. Extend SQL
The Nextval Macro
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4. Extend SQL
Take-aways

• The input( ) function converts its character
  argument to a numeric value.
• The resolve( ) function processes a macro
  expression (in this case the nextval macro
  program) and returns any text produced.
• The argument to the resolve( ) function is in
  single quotes so it does not get processed until
  run time.

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5. Pure Macros
without data steps
demo5_QueryDescriptor.sas
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5. Pure Macros
The obsnvars Macro
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5. Pure Macros
Take-aways

• global and local allow you to determine where
  macro variables are stored.
• sysfunc( ) allows the macro processor to use
  data step functions directly.
• Open( ), attrn( ) and close( ) functions access
  the data set and read attribute values from the
  descriptor.
• sysfunc(sysmsg( ) ) captures error message text.

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6. Recursive Programming
http//www.mantasoft.co.uk/_stuff/Recursive.htm
n!
n! gamma(n1)
demo6_Factorial.sas
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7. Divide Conquer
Not Sorted
Not Sorted
SORT
SORT
Sorted
Sorted
demo7_DivideAndConquer.sas
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7. Divide Conquer
The actual input data
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7. Divide Conquer
demo7_DivideAndConquer.log
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7. Divide Conquer
Take Away

• sysfunc(time(),best15.) allows the macro
  processor to use data step functions directly and
  format the result.
• sysevalf(to - from) performs floating-point
  arithmetic and returns a value that is formatted
  using the BEST32. format.
• sysfunc(putn(sysevalf(to - from),time12.3)).
  sysfunc cannot format the result of the
  sysevalf since it is expecting a function as
  argument reason why we must used putn.

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7. Divide Conquer
PROC SORT TIME -gt 02220.658
SORT MACRO TIME -gt 00921.227
A SAVING OF 01259 (58)
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7. Divide Conquer
The SORT macro
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7. Divide Conquer
Take Away

• macro sort(dsnin,dsnout,by,maxrec) allows
• passing parameters by position

call symput('dsn' trim(left(put(i,3.))), '___'
trim(left(put(i,3.))))

• The macro variables dsn1, dsn2, dsn3 dsnn will
  contain ___1, ___2, ___3 ___n the name of
  the temporary sorted datasets.
• NB_WRK is the number of temporary datasets.
• MAXREC is the maximum number of observation per
  Sort.
• NOBS is the total number of observations to be
  sorted from the input dataset.

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7. Divide Conquer
The SORT macro
1 Dataset having a length of less than MAXREC
Split Dataset into Several Sub-datasets While Sort
ing
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7. Divide Conquer
The SORT macro
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7. Divide Conquer
The SORT macro
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How To Learn More

• Instructor based training
• http//support.sas.com/training/Canada
• Next SAS Macro Language, a two-day course,
  starting on
• February 25th in Montreal
• February 2nd in Ottawa
• December 15th in Toronto
• Next SAS Macro Language Advanced Topics, a
  one-day course on
• March 26th in Montreal
• February 11th in Ottawa and
• February 16th in Toronto

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How To Learn More

• Instructor based training
• http//support.sas.com/training/Canada
• Next SAS Macro Language, a two-day course,
  starting on
• February 25th in Montreal
• February 2nd in Ottawa
• December 15th in Toronto
• Next SAS Macro Language Advanced Topics, a
  one-day course on
• March 26th in Montreal
• February 11th in Ottawa and
• February 16th in Toronto

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How To Learn More

• Technical Support
• http//support.sas.com/techsup/intro.html
• http//support.sas.com/techsup/faq/macro.html

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How To Learn More

• Books
• SAS Guide to Macro Processing 56041
• SAS Macro Language Reference 55501
• SAS Macro Facility Tips Techniques 55097
• Carpenters Complete Guide to the SAS Macro
  Language 56100

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Questions ?