Corticon.js's Collection operators are as follows:

Name and Syntax Returns Description
Replace element(s)

<Collection1> = <Collection2>

<Collection1> = <Entity>

modifies a collection replaces all elements in <Collection1> with elements of <Collection2> or with <Entity>, provided the new associations are allowed by the Business Vocabulary.
Associate element(s)

<Collection1> += <Collection2>

<Collection1> += <Entity>

modifies a collection Associates all elements of <Collection2> or <Entity> with <Collection1>. Every <Collection> must be expressed as a unique alias.
Disassociate element(s)
<Collection1> -= <Collection2> modifies a collection Disassociates all elements of <Collection2> from <Collection1>. Does not delete the disassociated elements. Every <Collection> must be expressed as a unique alias.
Is empty
<Collection> ->isEmpty Boolean Returns a value of true if <Collection> contains no elements
Not empty
<Collection> ->notEmpty Boolean Returns a value of true if <Collection> contains at least one element.
Exists
<Collection> ->exists (<Expression>) Boolean Returns a value of true if <Expression> holds true for at least one element of <Collection>
For all
<Collection> ->forAll (<Expression>) Boolean Returns a value of true if every <Expression> holds true for every element of <Collection>
Sorted by
<Collection> ->sortedBy (<Attribute>) converts a collection into a sequence

Sequences the elements of <Collection> in ascending order, using the value of <Attribute> as the index. <Collection> must be expressed as a unique alias.
Sorted by descending
<Collection> ->sortedByDesc (<Attribute>) converts a collection into a sequence Sequences the elements of <Collection> in descending order, using the value of <Attribute> as the index. <Collection> must be expressed as a unique alias.
Size of collection
<Collection> ->size Integer Returns the number of elements in <Collection>. <Collection> must be expressed as a unique alias.
Sum
<Collection.attribute> ->sum Number Sums the values of the specified <attribute> for all elements in <Collection>. <attribute> must be a numeric data type.
Average
<Collection.attribute> ->avg Number Averages all of the specified attributes in <Collection>. <Collection> must be expressed as a unique alias. <attribute> must be a numeric data type
Minimum
<Collection.attribute> ->min Number Returns the lowest value of <attribute> for all elements in <Collection>. <attribute> must be a numeric data type
Maximum
<Collection.attribute> ->max Number Returns the highest value of <attribute> for all elements in <Collection>. <attribute> must be a numeric data type