CALL DYNAMIC_ARRAY Routine

Enables an array that is declared within a function to change size in an efficient manner.

Category:

Array

Syntax

Details

Example

Syntax

CALL DYNAMIC_ARRAY(array–name, new-dim1–size, ...,, new-dimN-size);

Required Arguments

array-name: specifies the name of a temporary array.

new-dim-size: specifies a new size for the temporary array.

Details

Arrays that are declared in functions and CALL routines can be resized, as well as arrays that are declared with the /NOSYMBOLS option. No other array can be resized.

The DYNAMIC_ARRAY CALL routine attempts to dynamically resize the array to match the dimensions of the target that you provide. This means that the array must be dynamic. That is, the array must be declared either in a function or subroutine, or declared with the /NOSYMBOLS option.

The DYNAMIC_ARRAY CALL routine is passed the array to be resized and a new size for each dimension of the array. In the ALLPERMK routine, a scratch array that is the size of the number of elements being permuted is needed. When the function is created, this value is not known because it is passed in as parameter n. A dynamic array enables the routine to allocate the amount of memory that is needed, instead of having to create an array that is large enough to handle all possible cases.

When using dynamic arrays, support is limited to PROC FCMP routines. When an array is resized, the resized array is available only within the routine that resized it. It is not possible to resize a DATA step array or to return a PROC FCMP dynamic array to the DATA step.

Example

The following example creates a temporary array named TEMP. The size of the array area depends on parameters that are passed to the function.

proc fcmp;
   function avedev_wacky(data[*]);

   length = dim(data);
   array temp[1] /nosymbols;
   call dynamic_array(temp, length);

   mean=0;
   do i=1 to datalen;
      mean += data[i];
      if i>1 then temp[i]=data[i-1];
      else temp[i]=0;
   end;
   mean=mean/length;

   avedev=0;
   do i=1 to length;
      avedev += abs((data[i])-temp[i] /2-mean);
   end;
   avedev=avedev/datalen;

   return(avedev);
endsub;
run;