In RPGLE (IBM i), %SUBARR is a built-in function (BIF) used to work with part of an array — basically a slice of an array.
🔍 What %SUBARR Does
%SUBARR returns a subset (portion) of an array, starting at a given element, and optionally for a given number of elements.
📘 Syntax
%SUBARR(array : start-index : number-of-elements)
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array → The array you want to slice.
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start-index → The starting element (1-based index).
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number-of-elements → (Optional) How many elements to include. If omitted, it takes everything from
start-indexto the end of the array.
✅ Examples
1. Copying part of an array
dcl-s Arr1 char(10) dim(5) inz(%array('A':'B':'C':'D':'E'));
dcl-s Arr2 char(10) dim(2);
Arr2 = %subarr(Arr1 : 2 : 2); // Arr2 = { 'B' , 'C' }
2. Processing a subarray in a loop
dcl-s numbers int(5) dim(6) inz(%array(10:20:30:40:50:60));
for-each value in %subarr(numbers : 3 : 2);
dsply value; // Will display 30 and 40
endfor;
3. Assigning values into part of an array
dcl-s base int(10) dim(5) inz(*zeros);
%subarr(base : 2 : 3) = %array(100:200:300);
// base = [0,100,200,300,0]
⚠️ Notes
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Index is 1-based (not 0-based like C or Java).
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If the subarray length goes beyond the array’s dimension, you’ll get a runtime error.
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Often used with
%LOOKUP,%XFOOT, or%ELEMfor advanced array handling.
✅ Summary:
%SUBARR lets you take a slice of an array (like arrays in Python, Java, or C#). It’s useful for assignments, looping over partial data, or manipulating chunks of arrays.