FOR MONDAY:

1

• FOR MONDAY
• Be prepared to hand in a one-page summary of the
  data you are going to use for your project and
  your questions to be addressed in the project
• Read Chapter 7 (7.1-7.5) on Macro-Programming
• macros allow you to make small changes in code
  that ripple throughout a long program
• macros allow you to write a piece of code once
  and reuse it many times over
• macros allow you to make you code data dependent
  - SAS decides what to do based on the values of
  the data.
• Practice macro writing on the project data

2
Macros and macro variables

• The macro processor resolves your macro code so
  it can generate legitimate SAS code.
• SAS macro code consists of macros and macro
  variables. Macro variables are prefaced with an
  ampersand () and macros are prefaced with a
  percent sign (). A macro can be a complex piece
  of code with DATA steps, PROC steps and macro
  statements like DO or LET, etc. A macro
  variable has only one value, always a character.

3
Macro variables

• Create a macro variable by using the LET
  statement. This is an efficient way to replace
  text strings in SAS...
• LET macro-variable-name text-value
• Then to use that particular text string in a SAS
  program refer to the macro variable with an
  ampersand (). Note quotes not required around
  the text-value.
• e.g., LET X freshman
• title Data analysis for the X Class

4

• NOTE the difference between a global and a local
  macro variable LET outside a macro definition
  defines a global variable. Otherwise, the macro
  variable is local.
• Try the example program on page 203 - note that
  the code only has to be changed in one place in
  the program.

5
Macro definitions

• Macros allow you to substitute text of SAS code
  within a SAS program.
• Each macro has a name and is defined between the
  MACRO and the MEND statements...
• E.g., MACRO macro-name
• macro-definition
• MEND macro-name
• To invoke the macro definition you defined as
  above, use the statement macro-name within
  your SAS program and the text in the
  macro-definition will be executed...

6

• See the example in Section 7.3 on p. 205.
• or this example
• macro plot
• proc plot plot totmassplantht run
• mend plot
• Later you may use this macro as
• data temp set save.padgett
• if marshph run
• plot
• proc print run etc.....

7

• The above macros would be much more useful if we
  could pick the variables we want to plot... this
  requires the use of parameters within the macro.
• E.g. macro plot(yvar ,xvar )
• proc plot plot yvarxvar run
• mend plot
• Then invoke the macro by referring to it and also
  inserting the specific variables you want to
  plot
• plot(yvartotmass, xvarplantht)
• Do the example on page 207 - the macro SELECT is
  created with 2 parameters creating 2 macro
  variables CUSTOMER and SORTVAR.

8

• Use the data (custID, sale date, variety sold,
  quantity)
• 240W 02-07-2003 Ginger 120
• 240W 02-07-2003 Protea 180
• 356W 02-08-2003 Heliconia 60
• 356W 02-08-2003 Anthurium 300
• 188R 02-11-2003 Ginger 24
• 188R 02-11-2003 Anthurium 24
• 240W 02-12-2003 Heliconia 48
• 240W 02-12-2003 Protea 48
• 356W 02-12-2003 Ginger 240

9

• We may use conditional logic in macros to write
  different code depending upon the value of
  certain macro variables for example
• MACRO dailyreports
• IF SYSDAY Monday THEN DO
• PROC PRINT DATA flowersales
• FORMAT SaleDate WORDDATE18.
• TITLE 'Monday Report Current Flower Sales'
  END
• ELSE IF SYSDAY Tuesday THEN DO
• PROC MEANS DATA flowersales MEAN MIN MAX
• CLASS Variety VAR Quantity
• TITLE 'Tuesday Report Summary of Flower Sales'
• END MEND dailyreports
• DATA flowersales
• INFILE 'c\MyRawData\TropicalSales.dat'
• INPUT CustomerID _at_6 SaleDate MMDDYY10. _at_17
  Variety 9. Quantity RUN dailyreports RUN

10

• Note that SAS creates automatic macro variables
  that you may use in your programs
• SYSDATE is the character value of the date that
  the session began
• SYSDAY is the character value of the day of the
  week that the session began
• end chapter 7 next time well do graphics