How to efficently create arrays with runs of equal elements in SAS -

case one

sample output:

`1,1,1,1,2,2,2,2......9,9,9,9,0,0,0,0'

a more general case be:

the array starts n1 elements valued x1, followed n2 elements valued x2...

in sample output, n1 = n2 = n3 = .. = 4, x1=1, x2=2 ...

but don't want create based on element's position in array using if-else statement.

here's have done:

%let nd = 80;  data _t(drop = i); array ap{&nd}; = 1 &nd; if le 4 a[i] = 1; else ....; end;  'other codes'  run;

case two

what if order in array doesn't matter long contains elements need (n1 x1, n2 x2 ...) ? in scenario, easier build array?

provided know in advance upper bound how many elements want create, can in array statement - e.g.

data _null_;     array t{10} (1*1 2*2 3*3 4*4);     put t{*}; run;

output:

1 2 2 3 3 3 4 4 4 4

n.b. sort of assignment implicitly causes array variables retained.

you can nest brackets when creating runs of elements, e.g,

data _null_;     array t{10} (2*(1 2 3 4 5));     put t{*}; run;

output:

1 2 3 4 5 1 2 3 4 5

however, * signs need separated brackets, e.g.

data _null_;     array t{10} (2*(1 2) 2*(3*3));     put t{*}; run;

output:

1 2 1 2 3 3 3 3 3 3

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