SubsetNew (UnicodeNamedArraylist function): Difference between revisions

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{{Template:UnicodeNamedArraylist:SubsetNew syntax}}
{{Template:UnicodeNamedArraylist:SubsetNew syntax}}
===Syntax terms===
===Syntax terms===
<dl>
<table class="syntaxTable">
<dt><i>%unamraylNew</i>
<tr><th><i>%unamraylNew</i></th>
<dd>A UnicodeNamedArraylist variable of the same type as the method
<td>A UnicodeNamedArraylist variable of the same type as the method UnicodeNamedArraylist (''%unamrayl'') to contain the items that are located by the search. If ''%unamraylNew'' is not empty, its contents are discarded before it is populated by the return items from SubsetNew. </td></tr>
UnicodeNamedArraylist (''%unamrayl'') to contain the items that are
<tr><th><i>%unamrayl</i></th>
located by the search.
<td>A UnicodeNamedArraylist object. </td></tr>
If ''%unamraylNew'' is not empty, its contents are discarded before it
<tr><th><i>criterion</i></th>
is populated by the return items from SubsetNew.
<td>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.
<dt><i>%unamrayl</i>
For example, <tt>LT(this, 91)</tt> is the criterion <tt>this</tt> <tt><</tt> <tt>91</tt>, where <tt>this</tt> is an identity function that simply returns the item's value. The items that satisfy this expression populate the UnicodeNamedArraylist that SubsetNew returns.
<dd>A UnicodeNamedArraylist object.
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 "[[SelectionCriterion class#Specifying a SelectionCriterion's parameters|Specifying a SelectionCriterion's parameters]]".</td></tr>
<dt><i>criterion</i>
</table>
<dd>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, <tt>LT(this, 91)</tt> is the
criterion <tt>this</tt> <tt><</tt> <tt>91</tt>, where
<tt>this</tt> is an identity function that simply returns the item's value.
The items that satisfy this expression populate the
UnicodeNamedArraylist that SubsetNew returns.
 
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 "[[SelectionCriterion class#Specifying a SelectionCriterion's parameters|Specifying a SelectionCriterion's parameters]]".
 
</dl>
==Usage notes==
==Usage notes==
<ul>
<ul>

Revision as of 23:09, 31 January 2011

Create UnicodeNamedArraylist of items matching some selection criteria (UnicodeNamedArraylist class)


This function searches the entire UnicodeNamedArraylist to find and return all items that match a specified criterion. The criterion is supplied by the SelectionCriterion object that is the required SubsetNew parameter. If no item satisfies the criterion, SubsetNew returns an empty UnicodeNamedArraylist.

Syntax

%outUniNal = uniNal:SubsetNew( selectionCriterion)

Syntax terms

%unamraylNew A UnicodeNamedArraylist variable of the same type as the method UnicodeNamedArraylist (%unamrayl) to contain the items that are located by the search. If %unamraylNew is not empty, its contents are discarded before it is populated by the return items from SubsetNew.
%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, 91) is the criterion this < 91, where this is an identity function that simply returns the item's value. The items that satisfy this expression populate the UnicodeNamedArraylist that SubsetNew returns.
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".

Usage notes

  • FindNextItem is similar to SubsetNew except that it returns just the first matching item it encounters.

Examples

In the following request, a SubsetNew call uses a selection criterion that first applies the intrinsic Length function to the collection items:

Begin %k is unicodeNamedArraylist of longstring %kk is unicodeNamedArraylist of longstring %k = new %k('§Jan':u) = 'Orion' %k('§Apr':u) = 'Leo' %k('§Mar':u) = 'Cancer' %k('§Jun':u) = 'Ursa Minor' %k('§Nov':u) = 'Andromeda' %k('§Dec':u) = 'Aries' %k('§Feb':u) = 'Canis Major' %sel is object selectionCriterion for longstring %n is float %sel = GE(length, 9) %kk = %k:subsetNew(%sel) %kk:print End

The result is:

1: &sect.Feb: Canis Major 2: &sect.Jun: Ursa Minor 3: &sect.Nov: Andromeda

See also