DYNAMIC ARRAY.sort

Sorts the rows in the array.

Syntax

sort( key STRING, reverse BOOLEAN )
  1. key is the name of a member of a structured array (DYNAMIC ARRAY OF RECORD), or NULL if the array is not structured.
  2. reverse is FALSE for ascending order, TRUE for descending order.

Usage

A dynamic array can be sorted with the sort() method.

  • For non-structured dynamic arrays (DYNAMIC ARRAY OF simple-type), the first argument of sort() must be NULL. The array will be sorted by the single-typed elements.
  • With structured arrays (DYNAMIC ARRAY OF RECORD), this method sorts the array by the member passed as first parameter.

Use the second parameter to define the sort order as ascending (FALSE) or descending (TRUE).

Character string data is sorted by following the collation rules defined by current application locale: The sort() method uses the operating system collation functions. Note that collation rules can slightly differ from platform to platform and therefore produce different ordering.

When making subsequent calls to the sort() method using different record members of the array, the rows will be ordered by all of the record members specified for the cumulative sorts, with the most recent call defining the main sort field.

Another way to think of this is in terms of the ORDER BY clause of a SQL statement: If your dynamic array contained the variables A, B and C, and you included the following calls to the sort() method:

CALL a.sort("C",false)
CALL a.sort("B",false)
CALL a.sort("A",false)

This would be equivalent to writing an ORDER BY clause that states:

ORDER BY A, B, C

Example

In this example, the first call to the sort() method sorts the rows by name in ascending order, and the second call will sort the rows by key in descendant order, then by name within each key. The last sort becomes the main sort field.

MAIN
  DEFINE a DYNAMIC ARRAY OF RECORD
               key INTEGER,
               name VARCHAR(30)
         END RECORD
  LET a[1].key = 776236    LET a[1].name = "aaaaa"
  LET a[2].key = 273434    LET a[2].name = "cccccccc"
  LET a[3].key = 934092    LET a[3].name = "bbbbb"
  CALL a.sort("name",FALSE) -- Sorted by name (asc order)
  CALL a.sort("key",TRUE) -- Sorted by key (desc), then by name
END MAIN