SYNTAX

<Collection> ->sortedBy(<Attribute2>) -> sequence operator.<Attribute1>

Sequences the elements of <Collection> in ascending order, using the value of <Attribute2> as the index, and returns the <Attribute1> value of the element in the sequence position determined by the sequence operator. A sequence must be created before any sequence operator ( ->first, ->last, or ->at) is used to identify a particular element. <Attribute1> and <Attribute2> must be attributes of <Collection>.

<Attribute2> may be any data type except Boolean. Strings are sorted according to character precedence. <Collection> must be expressed as a unique alias.

See Advanced collection sorting syntax in the Rule Modeling Guide for more examples of usage.

The Operators row of the table in Summary Table of Vocabulary Usage Restriction applies. No special exceptions.

This sample Rulesheet uses ->sortedBy in a conditional expression to create an ascending sequence from collection with decimal1 as the index.  ->first.string1 is used to return the value of the string1 attribute of the first element of the sequence. If the value of string1 is Joe, then boolean1 attribute of Entity1 is assigned the value of true.

A sample Ruletest provides a collection of three elements, each with a decimal1 and string1 value. Input and Output panels are shown below.

This sample Rulesheet uses ->sortedBy in an action expression to create an ascending sequence from collection with decimal1 as the index. ->first.string1 is used to return the value of the string1 attribute of the first element of the sequence. The value of string1 is assigned the value of Joe if boolean1 attribute of Entity1 is true, if false it is assigned the value of Mary.

A sample Ruletest provides a collection of three elements, each with a decimal1 and string1 value. Input and Output panels are shown below.