FindPreviousItemNumber (FloatNamedArraylist function): Difference between revisions

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<span style="font-size:120%; color:black"><b><section begin=dpl_desc/>Return num<section end=dpl_desc/></b></span>
#REDIRECT [[FindPreviousItemNumber (GenericNamedArraylist function)]]
[[Category:FloatNamedArraylist methods|FindPreviousItemNumber function]]
<!--DPL?? Category:FloatNamedArraylist methods|FindPreviousItemNumber function: Return num-->
<p>
FindPreviousItemNumber is a member of the [[FloatNamedArraylist class]].
</p>
 
This function searches &ldquo;backward&rdquo; in the FloatNamedArraylist to find and
return the item number of the next item that matches a specified criterion.
The criterion is supplied by the [[SelectionCriterion class|SelectionCriterion]] object
that is a required FindPreviousItemNumber parameter.
If no item satisfies the criterion,
the method returns a zero.
 
FindPreviousItemNumber is available in ''Sirius Mods'' version 7.6 and later.
==Syntax==
  %itemnum = %fnamrayl:FindPreviousItemNumber(criterion  -
                                      [,&nbsp;Start=itemnum])
===Syntax Terms===
<dl>
<dt><i>%itemnum</i>
<dd>A numeric variable to contain the item number of 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, 1)</tt> is the
criterion <tt>this</tt> <tt><</tt> <tt>1</tt>, where
<tt>this</tt> 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 ''%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 2 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 method returns a zero.
<li>[[FindNextItemNumber (FloatNamedArraylist function)|FindNextItemNumber]]
is identical to FindPreviousItemNumber except that it searches forward in
the FloatNamedArraylist.
</ul>
==Examples==
 
See the [[FindNextItemNumber (FloatNamedArraylist function)#Examples|FindNextItemNumber example]] for an example with a FindPreviousItemNumber call.

Latest revision as of 20:36, 5 August 2012