| Processing Variables with Arrays |
| Expanding Your Use of
Arrays |
During the compilation of the DATA step, the variables created with this
ARRAY statement are added to the program data vector and are stored in the
resulting data set.
data hrd.diff;
set hrd.convert;
array wt(6) weight1-weight6;
array WgtDiff(5);
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When referencing the array elements, be careful not to confuse
the array references WgtDiff(1) through
WgtDiff(5) (note parentheses) with the variable
names WgtDiff1 through WgtDiff5. The program
data vector below shows the relationship between the array references and
the corresponding variable names. |
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Now you can use a DO loop to calculate the differences between each of
the recorded weights. Notice that each value of
WgtDiff(i) is calculated by subtracting
wt(i) from wt(i+1). By manipulating
the index variable, you can easily reference any array element.
data hrd.diff;
set hrd.convert;
array wt(6) weight1-weight6;
array WgtDiff(5);
do i=1 to 5;
WgtDiff(i)=wt(i+1)-wt(i);
end;
run;
A portion of the resulting data set is shown below. |
SAS Data Set Hrd.Diff
Name
WgtDiff1
WgtDiff2
WgtDiff3
WgtDiff4
WgtDiff5
Alicia
-1.54322
-0.22046
-3.08644
-3.08644
0.44092
Betsy
0.00000
-1.98414
-2.86598
-1.32276
-1.54322
Brenda
-2.20460
-1.32276
-1.32276
-1.32276
-1.32276
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Copyright © 2002 SAS Institute Inc.,
Cary, NC, USA. All rights reserved.