FindPreviousItem (FloatNamedArraylist function): Difference between revisions

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Revision as of 18:17, 5 January 2011

<section begin=dpl_desc/>Find matching list ite<section end=dpl_desc/>

FindPreviousItem is a member of the FloatNamedArraylist class.

This function searches “backward” in the FloatNamedArraylist to find and return the next item that matches a specified criterion. The criterion is supplied by the SelectionCriterion object that is a required FindPreviousItem parameter. If no item satisfies the criterion, the request is cancelled and an ItemNotFound exception (?? refid=itemnfe.) is thrown.

FindPreviousItem is available in Sirius Mods version 7.6 and later.

Syntax

  %item = %fnamrayl:FindPreviousItem(criterion        -
                                     [, Start=itemnum])

Syntax Terms

%item
A variable of the type of the items in the FloatNamedArraylist to contain the item that is located by the search.
%fnamrayl
A FloatNamedArraylist object.
criterion
A SelectionCriterion object, which is a relational expression that is applied to a %fnamrayl item value to determine whether the value satisfies the expression. The expression consists of a function, an operator, and a numeric or string value. For example, LT(this, 11) is the criterion this < 11, where this is an identity function that simply returns the item's value. The first item tested by FindPreviousItem that satisfies this expression is the method's return value. The function in the criterion is a method value (a method or class member name literal, or a method variable) for a method that operates on items of the type specified on the %fnamrayl declaration and that returns a numeric or string value. This is described further in "Specifying a SelectionCriterion's parameters".
Start= itemnum
The number of the item before which to begin the search. If the itemnum value of Start is 4, item 3 is the first item considered. The value of Start may be 1 through one plus the number of items in the FloatNamedArraylist. For a collection of three items, itemnum may be 1, 2, 3, or 4. This is an optional argument, and it defaults to one plus the number of items in the FloatNamedArraylist. If you specify a value, the parameter name Start is required.

Usage Notes

  • If the value of Start is not in the range of 1 through one plus the number of items in the FloatNamedArraylist, the request is cancelled. If the value of Start is 1, no item can be found and the request is cancelled, but an ItemNotFound exception is thrown.
  • FindNextItem is identical to FindPreviousItem except that it searches forward in the FloatNamedArraylist.

Examples

In the following fragment, a FindPreviousItem call is applied to a FloatNamedArraylist of objects of the annual class that is defined in the request in the "FloatNamedArraylist Minimum function example".

    %fann is floatnamedArraylist of object annual
    %fann = new
    %fann(12) = newa(621, 650)
    %fann(14) = newa(334, 343)
    %fann(15) = newa(288, 276)
    %fann(13) = newa(141, 182)
    %fann(11) = newa(131, 115)

    %sel is object selectionCriterion for object annual
    %sel = LT(chg, 0)

    %ann is object annual
    %ann = %fann:findPreviousItem(%sel, start=4)
    print %ann:myprint

The result is:

    ybegin=131, yend=115