FindPreviousItem (FloatNamedArraylist function): Difference between revisions

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<span style="font-size:120%; color:black"><b><section begin=dpl_desc/>Find matching list ite<section end=dpl_desc/></b></span>
#REDIRECT [[FindPreviousItem (GenericNamedArraylist function)]]
[[Category:FloatNamedArraylist methods|FindPreviousItem function]]
<!--DPL?? Category:FloatNamedArraylist methods|FindPreviousItem function: Find matching list ite-->
<p>
FindPreviousItem is a member of the [[FloatNamedArraylist class]].
</p>
 
This function searches &ldquo;backward&rdquo; in the FloatNamedArraylist to find and return
the next item that matches a specified criterion.
The criterion is supplied by the [[SelectionCriterion class|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        -
                                      [,&nbsp;Start=itemnum])
===Syntax Terms===
<dl>
<dt><i>%item</i>
<dd>A variable of the type of the items in the FloatNamedArraylist to contain the
item that is located by the search.
<dt><i>%fnamrayl</i>
<dd>A FloatNamedArraylist object.
<dt><i>criterion</i>
<dd>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, <tt>LT(this, 11)</tt> is the
criterion <tt>this</tt> <tt><</tt> <tt>11</tt>, where
<tt>this</tt> 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 "[[SelectionCriterion class#Specifying a SelectionCriterion's parameters|Specifying a SelectionCriterion's parameters]]".
<dt><b>Start=</b><i> itemnum</i>
<dd>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 <tt>Start</tt> is required.
 
</dl>
==Usage Notes==
<ul>
<li>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.
<li>[[FindNextItem (FloatNamedArraylist function)|FindNextItem]]
is identical to FindPreviousItem except that it searches forward
in the FloatNamedArraylist.
</ul>
==Examples==
 
In the following fragment, a FindPreviousItem call is applied to a
FloatNamedArraylist
of objects of the <tt>annual</tt> class that is defined in the
request in the "[[Minimum (FloatNamedArraylist function)#Examples|FloatNamedArraylist Minimum function example]]".
<pre style="xmp">
    %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
</pre>
 
The result is:
<pre style="xmp">
    ybegin=131, yend=115
</pre>

Latest revision as of 20:32, 5 August 2012