SortNew (Arraylist function): Difference between revisions

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{{Template:Arraylist:SortNew subtitle}}
{{Template:Arraylist:SortNew subtitle}}


This function sorts the method object <var>Arraylist</var> and returns the sorted result in a new <var>Arraylist</var>.  The sort is based on one or more sort [[SortOrder class|criteria]] which consist of a sorting direction (ascending or descending) paired with a sort key (a function that gets applied to each <var>Arraylist</var> item).  Each sort criterion pair is a [[SortOrder class|SortOrder object]], and multiple pairs are a <var>SortOrder</var> collection.
<var>SortNew</var> sorts the method object <var>Arraylist</var> returning the sorted result in a new <var>Arraylist</var>.  The sort is based on one or more sort criteria, each of which consists of a sorting direction (ascending or descending) paired with a sort key (a function that gets applied to an <var>Arraylist</var> item).  The sort criteria pairs are passed to <var>SortNew</var> as a <var>[[SortOrder class|SortOrder]]</var> argument.
 
<p>Each sort key function (which is applied to the <var>Arraylist</var> items) must operate on the item type and return an <var>[[Intrinsic classes|intrinsic]]</var> datatype (<var>Float</var>, <var>String</var>, <var>Longstring</var>, or <var>Unicode</var>) value. The values returned by the function are sorted into ascending or descending order to determine the position of their associated item in the new <var>Arraylist</var>.</p>
The sort key function that gets applied to each <var>Arraylist</var> item, which you identify in the <var>SortNew</var> parameter, must operate on the item type and return a User Language [[Intrinsic classes|intrinsic datatype]] (<var>Float</var>, <var>String</var>, <var>Longstring</var>, or <var>Unicode</var>) value. The values returned by the function are sorted into ascending or descending order to determine the position of their associated item in the new <var>Arraylist</var>.
 
The system intrinsic classes are discussed in "[[Intrinsic classes]]".


==Syntax==
==Syntax==
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===Syntax terms===
===Syntax terms===
<table class="syntaxTable">
<table class="syntaxTable">
<tr><th><i>%newList</i></th>
<tr><th>%newList</th>
<td>An <var>Arraylist</var> object to contain the sorted <var class="term">al</var> items.</td></tr>
<td>A newly create <var>Arraylist</var> object to contain the sorted <var class="term">al</var> items.</td></tr>
<tr><th><i><var class="term">al</var></i></th>
<tr><th>al</th>
<td>The input <var>Arraylist</var> object.</td></tr>
<td>The input <var>Arraylist</var> object.</td></tr>
<tr><th><i>sortOrder</i></th>
<tr><th>sortOrder</th>
<td>One or more <var>SortOrder</var> objects, which consist of an ordering direction for the sort and a key to sort by, specified in the form: <var class="term">order(key)</var>. The <var class="term">order</var> is either <code>Ascending</code> or <code>Descending</code>, and the <var class="term">key</var> is a function that is applied to each item in the <var>al</var>. For example:
<td>A <var>SortOrder</var> object, which consists of one or more pairs of an ordering direction for the sort and a sort key function. For example:
<p class="code">%alist = %alist:sortnew(descending(length))
<p class="code">%alist = %alist:sortnew(descending(length))
</p>
</p>
The function is a method value (a method or class member name literal, or a method variable) for a method that operates on objects of the type specified on the <var class="term">al</var> declaration and that returns a numeric or string value. This is described further in "[[SortOrder class#Specifying a SortOrder's sort key method|Specifying a SortOrder's sort key method]]".</td></tr>
The function is a method value (a method or class member name literal, or a method variable) for a method that operates on objects of the type specified on the <var class="term">al</var> declaration and that returns a numeric or string value. This is described further in [[SortOrder class#Specifying a SortOrder's sort key method|"Specifying a SortOrder's sort key method"]].
 
A <var>SortOrder</var> with multiple sort criteria can be specified using the <var>[[List (SortOrder function)|List]]</var> function.
</td></tr>
</table>
</table>


==Usage notes==
==Usage notes==
<ul>
<ul>
<li>If the function applied by <var>sortNew</var> returns string values, <var>sortNew</var> uses the decimal-equivalent value of the character bytes to determine the ascending or descending alphabetic order of the associated <var class="term">al</var> items. In ascending order, the highest or last lowercase letter is <code>'z'</code>; the highest or last uppercase letter is <code>'Z'</code>; <code>'z'</code> ranks lower than all the uppercase letters; and all letters rank lower than any number.
<li>If the function applied by <var>sortNew</var> returns <var>String</var> or <var>Unicode</var> values, <var>SortNew</var> uses the collating sequence of EBCDIC or Unicode, respectively, to determine the ascending or descending alphabetic order of the associated <var class="term">al</var> items. If the function returns a numeric type, numeric comparisons are used.
 
<li>If two or more <var class="term">al</var> items have equal values after all sort criteria are applied, <var>sortNew</var> returns them in the same order in which they appear in the input <var class="term">al</var>.
<li>If two or more <var class="term">al</var> items have equal values after all sort criteria are applied, <var>sortNew</var> returns them in the same order in which they appear in the input <var class="term">al</var>.
<li>The function in the parameter for <var>SortNew</var> is a method value, not a User Language expression.  That is, you cannot provide a function that itself has an argument (say, <code>Char(13)</code>) as the <var>SortNew</var> parameter.
 
<li>As of <var class="product">Sirius Mods</var> version 7.6, the default ''sortCriteria'' argument is the <var>SortOrder</var> <code>Ascending(This)</code>, where <code>This</code> is the identity function described further in "[[Collections#Using the This function as the Maximum parameter|Using the This function as the Maximum parameter]]". Therefore, <code><var class="term">al</var>:sortnew(ascending(this))</code> can be specified simply as <code><var class="term">al</var>:sortnew</code>, as shown in the [[#Examples|example]] below.
<li>The function in the parameter for <var>SortNew</var> is a method value, not a <var class="product">User Language</var> expression.  That is, you cannot provide a function that, itself, also has an argument (say, <code>Char(13)</code>) as the <var>SortNew</var> parameter.
<li><var>SortNew</var> is available in <var class="product">Sirius Mods</var> version 7.3 and later.
 
<li>As of <var class="product">[[Sirius Mods|Sirius Mods]]</var> Version 7.6, the default <var class="term">sortOrder</var> argument is the <var>SortOrder</var> <code>Ascending(This)</code>, where <var>This</var> is the identity function value described further in [[Collections#Using the This function as the Maximum parameter|"Using the This function as the Maximum parameter"]]. Therefore, <code><var class="term">al</var>:sortnew(ascending(this))</code> can be specified simply as <code><var class="term">al</var>:sortnew</code>, as shown in the [[#Examples|example]] below.
 
<li><var>SortNew</var> is available in <var class="product">Sirius Mods</var> Version 7.3 and later.
</ul>
</ul>


==Examples==
==Examples==
<ol><li>
<ol><li>
The following simple example shows the default sort of an arraylist of integers. <var>Sortnew</var> is specified with no explicit argument, and <code>ascending(this)</code> is the <var>SortOrder</var> argument that is invoked:
The following simple example shows the default sort of an <var>arraylist</var> of integers. <var>Sortnew</var> is specified with no explicit argument, and <code>ascending(this)</code> is the <var>SortOrder</var> argument that is invoked:
<p class="code">begin
<p class="code">begin
   %al    is arraylist of float
   %al    is arraylist of float
   %al2  is arraylist of float
   %al2  is arraylist of float
   %i    is float
   %i    is float
 
   %al = list(9, 11, 4, -5, 17, 3, 6)
   %al = list(9, 11, 4, -5, 17, 3, 6)
   %al2 = %al:sortnew
   %al2 = %al:sortnew
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17
17
</p>
</p>
<li>For more examples of the <var>SortNew</var> method, see [[Collections#Finding collection maxima and minima, and sorting|Finding collection maxima and minima, and sorting]].</ol>
<li>For more examples of the <var>SortNew</var> method, see [[Collections#Finding collection maxima and minima, and sorting|"Finding collection maxima and minima, and sorting"]].</ol>


==See also==
==See also==
<ul><li><var>[[Sort (Arraylist subroutine)|Sort]]</var> is a subroutine that works like the <var>sortNew</var> function but applies the sort to the method object instead of returning a new <var class="term">al</var>.</ul>
<ul><li><var>[[Sort (Arraylist subroutine)|Sort]]</var> which works like the <var>sortNew</var> function but applies the sort to the method object instead of returning a new <var class="term">al</var>.</ul>
{{Template:Arraylist:SortNew footer}}
{{Template:Arraylist:SortNew footer}}

Latest revision as of 19:36, 13 August 2012

Return new sorted Arraylist (Arraylist class)


SortNew sorts the method object Arraylist returning the sorted result in a new Arraylist. The sort is based on one or more sort criteria, each of which consists of a sorting direction (ascending or descending) paired with a sort key (a function that gets applied to an Arraylist item). The sort criteria pairs are passed to SortNew as a SortOrder argument.

Each sort key function (which is applied to the Arraylist items) must operate on the item type and return an intrinsic datatype (Float, String, Longstring, or Unicode) value. The values returned by the function are sorted into ascending or descending order to determine the position of their associated item in the new Arraylist.

Syntax

%newList = al:SortNew[( [sortOrder])]

Syntax terms

%newList A newly create Arraylist object to contain the sorted al items.
al The input Arraylist object.
sortOrder A SortOrder object, which consists of one or more pairs of an ordering direction for the sort and a sort key function. For example:

%alist = %alist:sortnew(descending(length))

The function is a method value (a method or class member name literal, or a method variable) for a method that operates on objects of the type specified on the al declaration and that returns a numeric or string value. This is described further in "Specifying a SortOrder's sort key method".

A SortOrder with multiple sort criteria can be specified using the List function.

Usage notes

  • If the function applied by sortNew returns String or Unicode values, SortNew uses the collating sequence of EBCDIC or Unicode, respectively, to determine the ascending or descending alphabetic order of the associated al items. If the function returns a numeric type, numeric comparisons are used.
  • If two or more al items have equal values after all sort criteria are applied, sortNew returns them in the same order in which they appear in the input al.
  • The function in the parameter for SortNew is a method value, not a User Language expression. That is, you cannot provide a function that, itself, also has an argument (say, Char(13)) as the SortNew parameter.
  • As of Sirius Mods Version 7.6, the default sortOrder argument is the SortOrder Ascending(This), where This is the identity function value described further in "Using the This function as the Maximum parameter". Therefore, al:sortnew(ascending(this)) can be specified simply as al:sortnew, as shown in the example below.
  • SortNew is available in Sirius Mods Version 7.3 and later.

Examples

  1. The following simple example shows the default sort of an arraylist of integers. Sortnew is specified with no explicit argument, and ascending(this) is the SortOrder argument that is invoked:

    begin %al is arraylist of float %al2 is arraylist of float %i is float %al = list(9, 11, 4, -5, 17, 3, 6) %al2 = %al:sortnew for %i from 1 to %al2:count print %al2(%i) end for end

    The result is:

    -5 3 4 6 9 11 17

  2. For more examples of the SortNew method, see "Finding collection maxima and minima, and sorting".

See also

  • Sort which works like the sortNew function but applies the sort to the method object instead of returning a new al.