SortNew (Arraylist function)

Return new sorted Arraylist (Arraylist class)

This function sorts the method object Arraylist and returns the sorted result in a new Arraylist. The sort is based on one or more sort criteria which consist of a sorting direction (ascending or descending) paired with a sort key (a function that gets applied to each Arraylist item). Each sort criterion pair is a SortOrder object, and multiple pairs are a SortOrder collection.

The sort key function that gets applied to each Arraylist item, which you identify in the SortNew parameter, must operate on the item type and return a User Language intrinsic datatype (Float, String, Longstring, or Unicode) value. The values returned by the function are sorted into ascending or descending order to determine the position of their associated item in the new Arraylist.

The system intrinsic classes are discussed in "Intrinsic classes".

Syntax

%newList = al:SortNew[( [sortOrder])]

Syntax terms

%newList	An Arraylist object to contain the sorted al items.
al	The input Arraylist object.
sortOrder	One or more SortOrder objects, which consist of an ordering direction for the sort and a key to sort by, specified in the form: order(key). The order is either Ascending or Descending, and the key is a function that is applied to each item in the al. For example: %alist = %alist:sortnew(descending(length)) The function is a method value (a method or class member name literal, or a method variable) for a method that operates on objects of the type specified on the al declaration and that returns a numeric or string value. This is described further in "Specifying a SortOrder's sort key method".

Usage notes

• If the function applied by sortNew returns string values, sortNew uses the decimal-equivalent value of the character bytes to determine the ascending or descending alphabetic order of the associated al items. Lowercase letters are first ranked alphabetically, then upper case letters, also ranked alphabetically, followed by the numbers; ie: 'a'..'z','A'..'Z',0..9.
• If two or more al items have equal values after all sort criteria are applied, sortNew returns them in the same order in which they appear in the input al.
• The function in the parameter for SortNew is a method value, not a User Language expression. That is, you cannot provide a function that itself has an argument (say, Char(13)) as the SortNew parameter.
• As of Sirius Mods version 7.6, the default sortCriteria argument is the SortOrder Ascending(This), where This is the identity function described further in "Using the This function as the Maximum parameter". Therefore, al:sortnew(ascending(this)) can be specified simply as al:sortnew, as shown in the example below.
• SortNew is available in Sirius Mods version 7.3 and later.

Examples

1. The following simple example shows the default sort of an arraylist of integers. Sortnew is specified with no explicit argument, and ascending(this) is the SortOrder argument that is invoked:

   begin %al is arraylist of float %al2 is arraylist of float %i is float %al = list(9, 11, 4, -5, 17, 3, 6) %al2 = %al:sortnew for %i from 1 to %al2:count print %al2(%i) end for end

   The result is:

   -5 3 4 6 9 11 17

2. For more examples of the SortNew method, see Finding collection maxima and minima, and sorting.

See also

• Sort is a subroutine that works like the sortNew function but applies the sort to the method object instead of returning a new al.

Arraylist class FloatNamedArraylist class NamedArraylist class UnicodeNamedArraylist class	List of Arraylist methods List of FloatNamedArraylist methods List of NamedArraylist methods List of UnicodeNamedArraylist methods List of Collection methods	Arraylist methods syntax FloatNamedArraylist methods syntax NamedArraylist methods syntax UnicodeNamedArraylist methods syntax
Notation conventions for methods