FindPreviousItemNumber (UnicodeNamedArraylist function)

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FindPreviousItemNumber is a member of the UnicodeNamedArraylist class.

This function searches “backward” in the UnicodeNamedArraylist to find and return the item number of the next item that matches a specified criterion. The criterion is supplied by the SelectionCriterion object that is a required FindPreviousItemNumber parameter. If no item satisfies the criterion, the method returns a zero.

Syntax

  %itemnum = %unamrayl:FindPreviousItemNumber(criterion  -
                                      [, Start=itemnum])

Syntax Terms

%itemnum

A numeric variable to contain the item number of the item that is located by the search.

%unamrayl

A UnicodeNamedArraylist object.

criterion

A SelectionCriterion object, which is a relational expression that is applied to a %unamrayl item value to determine whether the value satisfies the expression. The expression consists of a function, an operator, and a User Language intrinsic type (numeric, string, or Unicode) value. For example, LT(this, 101) is the criterion this < 101, where this is an identity function that simply returns the item's value. The item number of the first item tested by FindPreviousItemNumber 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 %unamrayl declaration and that returns an intrinsic 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 UnicodeNamedArraylist. 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 UnicodeNamedArraylist. If you specify a value, the parameter name Start is required.

Usage Notes

• If the value of Start is not in the range of 2 through one plus the number of items in the UnicodeNamedArraylist, the request is cancelled. If the value of Start is 1, no item can be found and the method returns a zero.
• FindNextItemNumber is identical to FindPreviousItemNumber except that it searches forward in the UnicodeNamedArraylist.

Examples

See the FindNextItemNumber example for an example with a FindPreviousItemNumber call.