Transcript SAS macro %_Count_

SAS macro %_COUNT_
Jim Groeneveld,
OCS Biometric Support,
Leiden, the Netherlands.
CC01 – PhUSE 2008
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SAS macro %_COUNT_
AGENDA / CONTENTS
1. Purpose: stating the problem
2. SPSS solution with COUNT
3. SAS alternative functionality
4. SAS additional functionality
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SAS macro %_COUNT_
PURPOSE: stating the problem
Counting the occurrence of many specific
values of specified variables in SAS data
step takes quite a lot of coding work.
Macro %_COUNT_ facilitates the process.
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SAS macro %_COUNT_
Counting values of variables
How often
do certain
numerical
or
character
values
occur in
specific
variables
within
records?
Var1
Var2
Var3
Var4
Count
4,5,6
1
2
3
4
1
5
6
7
8
2
VarA
VarB
VarC
a
b
c
d
3
e
f
g
h
2
4
VarD Count
'b'-'f'
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SAS macro %_COUNT_
SPSS solution with COUNT (1)
SPSS has the command COUNT, syntax:
• simple form (example):
COUNT Countvar = var_a, var_b [...]
(value_1, value_2, value_3 [...]).
• general form:
COUNT CountVar = variable_list
(value_list) [... (...) [... (...)]]
[/...=... (...) [... (...)]] [/...].
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SAS macro %_COUNT_
SPSS solution with COUNT (2)
in which a variable_list consists of:
variables names | implied consecutive
variable list: variable_1 TO variable_N;
and in which a value_list consists of:
separate either numeric or character
values | range(s) of values with THRU,
including LO and HI for one-sidedness.
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SAS macro %_COUNT_
SPSS solution with COUNT (3)
SPSS COUNT, complex example:
COUNT
Counter1 = NumA, NumB (0, MISSING) /
Counter2 = NumC, NumD, NumE TO NumI
(3, 5 THRU 9, 14 THRU HI, SYSMIS)
CharA, CharB, CharC TO CharH, CharI
('a text', 'b text', "any!@#$") .
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SAS macro %_COUNT_
SAS alternative functionality (1)
(approx.) equivalent SAS only code:
Counter1 = (NumA=0) + MISSING(NumA) + (NumB=0) + MISSING(NumB);
Counter2 = (NumC EQ 3) + (NumC>=5 AND NumC<=9) + (NumC>=14) + MISSING(NumC)
+ (NumD EQ 3) + (NumD>=5 AND NumD<=9) + (NumD>=14) + MISSING(NumD)
+ (NumE EQ 3) + (NumE>=5 AND NumE<=9) + (NumE>=14) + MISSING(NumE)
+ (NumF EQ 3) + (NumF>=5 AND NumF<=9) + (NumF>=14) + MISSING(NumF)
+ (NumG EQ 3) + (NumG>=5 AND NumG<=9) + (NumG>=14) + MISSING(NumG)
+ (NumH EQ 3) + (NumH>=5 AND NumH<=9) + (NumH>=14) + MISSING(NumH)
+ (NumI EQ 3) + (NumI>=5 AND NumI<=9) + (NumI>=14) + MISSING(NumI)
+ (CharA IN('a text', 'b text', "any!@#$"))
+ (CharB IN('a text', 'b text', "any!@#$"))
+ (CharC IN('a text', 'b text', "any!@#$"))
+ (CharD IN('a text', 'b text', "any!@#$"))
+ (CharE IN('a text', 'b text', "any!@#$"))
+ (CharF IN('a text', 'b text', "any!@#$"))
+ (CharG IN('a text', 'b text', "any!@#$"))
+ (CharH IN('a text', 'b text', "any!@#$"))
+ (CharI IN('a text', 'b text', "any!@#$")) ;
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SAS macro %_COUNT_
SAS alternative functionality (2)
(approx.) equivalent %_Count_ code:
%_COUNT_ ((
Counter1 = NumA, NumB (0, _SYSMIS_) /
Counter2 = NumC NumD NumE _TO_ NumI
(3 5 _THRU_ 9 14 _THRU_ _HI_ _SYSMIS_)
CharA, CharB, CharC _TO_ CharH, CharI
('a text', 'b text', "any!@#$").));
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SAS macro %_COUNT_
SAS alternative functionality (3)
Syntax conversion from SPSS to SAS:
SAS macro %_Count_ supports the same
syntax and functionality as the SPSS
command COUNT. Keywords start and
end with _underscores_ and the concept
of missing values differs between SPSS
and SAS, but that is not relevant.
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SAS macro %_COUNT_
SAS alternative functionality (4)
Comparable features of macro %_Count_
a. full syntax and functionality support;
b. any constant character value text;
c. missing value support with _SYSMIS_;
d. support of implied, consecutive, same
type variable lists: _TO_-convention;
e. f. support of (numeric) value ranges:
_THRU_-convention; _LO_ and _HI_.
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SAS macro %_COUNT_
SAS additional functionality
Extraneous features of macro %_Count_:
a. lexicographic comparison of character
values with the _THRU_ keyword;
b. variables in value (range) lists (no TO)
c. constant values in variable list (no TO)
d. array elements as variables, except
with an implied list (_TO_-convention)
e. SAS name literals instead of variables.
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SAS macro %_COUNT_
SAS use of macro %_Count_
Macro %_Count_ call within data step:
1. SPSS-like code between double left
and right parentheses: one set to start
the macro and the other set to contain
the whole SPSS-like code as one value
for the main, first, positional macro
argument that is parsed by the macro;
2. newer versions will contain some bells
and whistles as additional arguments.
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Q&A: SAS macro %_COUNT_
QUESTIONS
&
ANSWERS
[email protected]
[email protected]
http://home.hccnet.nl/jim.groeneveld/count
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Q&A: SAS macro %_COUNT_
Origin of SAS macro %_Count_
1. SPSS experience from 1975 to 1997;
a.
b.
c.
d.
mainframe versions, command language;
SPSS/PC, command language oriented;
SPSS for Windows with graphical user interface;
SPSS9toX: SPSS-9 to SPSS-X syntax converter;
2. SAS experience since 1997 (to date);
a.
b.
c.
d.
contributor to SAS-L (comp.soft-sys.sas);
aware of nice SPSS features lacking in SAS;
needed functionality like COUNT (and RECODE);
much experience with writing SAS macros.
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Q&A: SAS macro %_COUNT_
Comparison of SPSS and SAS missings
SPSS – numeric and short strings:
• user defined: any values per variable
(up to three, or one plus a range)
• system missing: automatically assigned
(just one) (not applicable to strings)
SAS - only fixed values:
• character: space
• numeric: ._ . .a to .z (28 ones in order)
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Q&A: SAS macro %_COUNT_
Algorithm of _TO_-convention
Hardly or not at all possible to let the
macro know the implied variable names
PROC CONTENTS, VARNUM and VARNAME
Macro does not need to know var names:
• %LET Incr = %IncrIndx; %* GLOBAL;
• ARRAY _0&Incr StartVar EndVar;
• DO _0_ = 1 TO DIM(_0&Incr); DROP _0_;
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Q&A: SAS macro %_COUNT_
SAS name literal
A SAS name literal is a name token that
is expressed as a string within
quotation marks, followed by the letter
n. For more information about SAS
name literals, see SAS Language
Reference: Concepts.
Example:
'This !@#$%^&* value'n = 0 ;
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Q&A: SAS macro %_COUNT_
Conversion Demonstration
To see the generated, converted SAS
code of a call to the macro %_Count_
(many macros actually) run the code:
%PUT {Start of generated code} %QUOTE(
/* the complete %_Count_ call here */
) {End of generated code} ;
All (unconditionally) generated SAS code
will appear in the log, not neatly
formatted, but logically working.
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Q&A: SAS macro %_COUNT_
Newer version's extra features
additional user specifiable arguments:
GlobIncr=_ArrayNr
/* name of unique
global incr. macro variable */,
ArPrefix=_0
/* prefix of unique
temporary SAS array for TO-list */,
IndexVar=_0_
/* name of unique
index variable for array elements */,
Sysmis=_SYSMIS_, To=_TO_, Thru=_THRU_,
Lo=_LO_, Hi=_HI_, Assign==, NewCount=/
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Q&A: SAS macro %_COUNT_
Additional unintended features
• Expressions without spaces, with +-*
involving constant and variable values:
Counter21 = a, b c (3, -5+7)
/* expression with constant values */
/ Counter22 = b, a b (c-a, 9)
/* expression with variables */
/ Counter23 = a+c (2*2) /* expression
in variable list as well */
Not at all guaranteed! No div., log. expr.?
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