The count aggregate returns a count of non-empty cells, or attributes that are not null.

Synopsis

AFL% aggregate(array,count(attribute)[,dimension_1,dimension_2,...])

AFL% aggregate(array,count(*) [,dimension_1,dimension_2,...])

Summary

When using the count(attribute) syntax, the empty cells and NULLs are not counted.

Examples

Find the Number of Non-Empty Cells or Non-Null values in an Array

1. Create an array of 1's except for the element at (0,1) which is NULL:

   AFL% store(build(<v:int8>[row=0:1; col=0:1],iif(row=0 and col=1,null,1)), M);

   
   The output is:

   {row,col} v
   {0,0} 1
   {0,1} null
   {1,0} 1
   {1,1} 1

2. Find the number of non-empty cells in the array:
   

   AFL% aggregate(M,count(*));

   
   The output is:
   

   {i} count
   {0} 4

3. Find the number of non-null values of attribute v in the array:

   AFL% aggregate(M,count(v));

   
   The output is:

   {i} count
   {0} 3

4. Find the number of nonempty and non-null cells for attribute v, per row:

   AFL% aggregate(M,count(v),row)

   
   The output is:
   

   {row} v_count
   {0} 1
   {1} 2

5. Find the number of nonempty and non-null cells for attribute v, per column:

   AFL% aggregate(M,count(v),col)

   
   The output is:

   {row} v_count
   {0} 2
   {1} 1

6. Remove the example array:

   AFL% remove(M)