sum

[HeatherNewton]

what does it mean when we specify values in sum?

I tried this and it does not add up, .. 

is there special meaning when we specify like this?

fruit=sum(apple='1',orange='2',lemon='3')

fruit is not 6 but show noting in output

[SASKiwi]

You can easily test how this works yourself:

28         data _null_;
29           apple = '1';
30           orange = '1';
31           fruit = sum(apple = '1', orange = '1');
32           put _all_;
33         run;

apple=1 orange=1 fruit=2 _ERROR_=0 _N_=1
NOTE: DATA statement used (Total process time):
      real time           0.01 seconds
      cpu time            0.01 seconds

Summing conditions like apple = '1' turns them into Boolean true = 1 or false = 0 values that are then added. 

[ballardw]

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@HeatherNewton wrote:

what does it mean when we specify values in sum?

I tried this and it does not add up, .. 

is there special meaning when we specify like this?

fruit=sum(apple='1',orange='2',lemon='3')

fruit is not 6 but show noting in output

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SAS returns 1 for a true result of a logical comparison and 0 for false. So when apple='1' you get a 1 and 0 otherwise. Summing these comparisons is a way to COUNT how many are true.

This internal creation of a numbers will execute much faster than a bunch of If/then/else that might be another attempt to count such as:

Count=0;
if apple='1' then count=count+1;
if orange='2' then count=count+1;
if lemon='3' then count=count+1;

By "tried this" how many different values of apple, orange and lemon did you try?