List functions list-functions

distinct(<listInteger>)

Returns a list of integers.

distinct(<listDecimal>)

Returns a list of decimals.

distinct(<listString>)

Returns a list of strings.

distinct(<listDateTimeOnly>)

Returns a list of datetimes without considering time zone.

distinct(<listDateTime>)

Returns a list of datetimes.

distinct(<listDateOnly>)

Returns a list of dates.

distinct(<listBoolean>)

Returns a list of booleans.

distinct(<listDuration>)

Returns a list of durations.

distinct(<listObject>)

distinct(<listObject>,<string>)

Returns a list of objects.

distinct([10,2,10,null])

Returns [10, 2].

distinctWithNull(<listInteger>)

Returns a list of integers.

distinctWithNull(<listDecimal>)

Returns a list of decimals.

distinctWithNull(<listString>)

Returns a list of strings.

distinctWithNull(<listDateTimeOnly>)

Returns a list of datetimes without considering time zone.

distinctWithNull(<listDateTime>)

Returns a list of datetimes.

distinctWithNull(<listDateOnly>)

Returns a list of dates.

distinctWithNull(<listBoolean>)

Returns a list of booleans.

distinctWithNull(<listDuration>)

Returns a list of durations.

distinctWithNull([10,2,10,null])

Returns [10, 2, null]

filter(listObject, string, listString)

filter(listObject, string, listInteger)

filter(listObject, string, listDecimal)

filter(listObject, string, listDateTime)

filter(listObject, string, listDateTimeOnly)

filter(listObject, string, listDateOnly)

filter(listObject, string, listDuration)

filter(listObject, string, listBoolean)

Returns a listObject.

Here is an example of a payload passed in an incoming event “myevent”:

"productListItems": [{
   "id": "product1",
   "name": "the product 1",
   "price": 20
},{
   "id": "product2",
   "name": "the product 2",
   "price": 30
},{
   "id": "product3",
   "name": "the product 3",
   "price": 50
}]

You can use the following expression:

filter(
 @event{myevent.productListItems},
 "id",
 ["product2", "product3", "product4"]
)

Returns a listObject containing the two objects with “product2” and “product3” as id.

getListItem(<listInteger>,<index>)

Returns an integer.

getListItem(<listDecimal>,<index>)

Returns a decimal.

getListItem(<listString>,<index>)

Returns a string.

getListItem(<listDateTimeOnly>,<index>)

Returns a datetime without considering time zone.

getListItem(<listDateTime>,<index>)

Returns a datetime.

getListItem(<listDateOnly>,<index>)

Returns a list of dates.

getListItem(<listBoolean>,<index>)

Returns a boolean.

getListItem(<listDuration>,<index>)

Returns a duration.

getListItem([10, 2, 3], 1)

Returns “2”

getListItem(["A", "B", "C"], 2)

Returns “C”

Examples with an event field ‘event.appVersion’ with value: “20.45.2.3434”

split(@event{event.appVersion}, "\\.")

Returns ["20", "45", "2", "3434"]

getListItem(split(@event{event.appVersion}, "\\."), 0)

Returns “20”

in(<integer>,<listInteger>)

in(<decimal>,<listDecimal>)

in(<string>,<listString>)

in(<boolean>,<listBoolean>)

in(<dateTimeOnly>,<listDateTimeOnly>)

in(<dateTime>,<listDateTime>)

in(<dateOnly>,<listDateOnly>)

in(<duration>,<listDuration>)

Return a boolean.

in(4,[4,5,3,4])

Returns true.

in(8,[4,5,3,4])

Returns false.

in(#{ExperiencePlatform.ProfileFieldGroup.profile.person.gender}, ["male"])

intersect(listString,listString): listString

intersect(listDecimal,listDecimal): listDecimal

intersect(listInteger,listInteger): listInteger

intersect(listDateTime,listDateTime): listDateTime

intersect(listDateTimeOnly,listDateTimeOnly): listDateTimeOnly

intersect(listDateOnly,listDateOnly): listDateOnly

intersect(listDuration,listDuration): listDuration

intersect(listBoolean,listBoolean): listBoolean

Returns a list.

intersect(
    ["sports", "news", "documentary"],
    ["sports", "movies", "documentary"]
)

Returns [“sports”, “news”]

intersect(
    #{ExperienceDataPlatform.profile.interests},
    ["sports", "documentary"]
)

Returns common items between profile attributes and given list of categories.

intersect(
    #{ExperienceDataPlatform.profile.interests},
        @event{myEvent.sport_interests}
)

Returns common items between profile attributes and given event field.

limit(<listString>,<integer>)

limit(<listString>,<integer>,<boolean>)

Returns a list of strings.

limit(<listInteger>,<integer>)

limit(<listInteger>,<integer>,<boolean>)

Returns a list of integers.

limit(<listDecimal>,<integer>)

limit(<listDecimal>,<integer>,<boolean>)

Returns a list of decimals.

limit(<listBoolean>,<integer>)

limit(<listBoolean>,<integer>,<boolean>)

Returns a list of booleans.

limit(<listDateOnly>,<integer>)

limit(<listDateOnly>,<integer>,<boolean>)

Returns a list of dates.

limit(<listDateTimeOnly>,<integer>)

limit(<listDateTimeOnly>,<integer>,<boolean>)

Returns a list of datetimes without considering time zone.

limit(<listDateTime>,integer>)

limit(<listDateTime>,<integer>,<boolean>)

Returns a list of datetimes.

limit(<listDuration>,<integer>)

limit(<listDuration>,<integer>,<boolean>)

Returns a list of durations.

limit(<listObject>,<integer>)

limit(<listObject>,<integer>,<boolean>)

Returns a list of objects.

limit(["A", "B", "C", "D", "E"], 3)

Returns ["A","B","C"].

limit(["A", "B", "C", "D", "E"], 3, false)

Returns ["C","D","E"].

listSize(<listInteger>)

listSize(<listDecimal>)

listSize(<listString>)

listSize(<listBoolean>)

listSize(<listDateTimeOnly>)

listSize(<listDateTime>)

listSize(<listDateOnly>)

listSize(<listDuration>)

Return an integer.

listSize(<listObject>)

listSize([10,2,3])

Returns 3.

listSize(@event{my_event.productListItems})

Returns the number of objects in the given array of objects (listObject type).

serializeList(<listInteger>,<string>,<boolean>)

serializeList(<listDecimal>,<string>,<boolean>)

serializeList(<listString>,<string>,<boolean>)

serializeList(<listBoolean>,<string>,<boolean>)

serializeList(<listDateTimeOnly>,<string>,<boolean>)

serializeList(<listDateTime>,<string>,<boolean>)

serializeList(<listDateOnly>,<string>,<boolean>)

serializeList(<listDuration>,<string>,<boolean>)

Return a string.

serializeList(["Hello","World"], " ", false)

Returns “Hello World”.

serializeList(["Hello", "World"], ",", true)

Returns ““Hello”,“World””.

sort(<listInteger>,<boolean>)

Returns a list of integers.

sort(<listDecimal>,<boolean>)

Returns a list of decimals.

sort(<listString>,<boolean>)

Returns a list of strings.

sort(<listDateTimeOnly>,<boolean>)

Returns a list of datetimes without considering time zone.

sort(<listDateTime>,<boolean>)

Returns a list of datetimes.

sort(<listDateOnly>,<boolean>)

Returns a list of dates.

sort(<listBoolean>,<boolean>)

Returns a list of booleans.

sort(<listObject>,<string>,<boolean>)

Returns a list of objects.

sort(["A", "C", "B"], true)

Returns ["A","B","C"].

sort([1, 3, 2], false)

Returns [3, 2, 1].

sort(@event{my_event.productListItems}, "SKU", true)

Returns the listObject ordered by SKU attribute (ascending order)

This section contains structured knowledge intended to support interpretation, retrieval, and question answering related to this topic.

For complete understanding, this information should be combined with the documentation on this page. Neither source is intended to stand alone; the page describes the feature, while this section provides additional context that helps disambiguate terminology, intent, applicability, and constraints.

• TL;DR: This page documents all list functions available in AJO journey expressions, covering how to filter, sort, deduplicate, check membership, limit, serialize, and find intersections of lists and arrays.

Intents:

• Remove duplicate values from a list using distinct (ignoring nulls) or distinctWithNull (preserving nulls)
• Filter a listObject to return only objects matching specific key values using filter
• Retrieve an element at a specific index from a list using getListItem
• Check whether a value exists in a list using in
• Find common elements between two lists using intersect
• Return the first or last N elements of a list using limit
• Count the total number of elements in a list using listSize
• Convert a list to a delimited string using serializeList
• Sort a list in ascending or descending order using sort

Glossary:

• listObject: A list of complex objects that must be a field reference; cannot contain null objects (product-specific)
• keyAttributeName: An optional string parameter used with distinct, filter, and sort to identify which object attribute to use for deduplication, filtering, or sorting (product-specific)
• intersect: A set operation returning only the elements present in both input lists

Guardrails:

• distinctWithNull does not support the <listObject> parameter type
• filter requires the listObject parameter to be a field reference, not an inline literal
• listSize on a listObject requires the list to be a field reference; a listObject cannot contain null objects
• serializeList does not support the listObject type

Terminology:

• Canonical name: List functions — Acronym: none — variants: collection functions, array functions
• Synonyms: “listSize” = “count list elements”; “serializeList” = “join list to string”
• Do not confuse: “distinct” (ignores nulls) ≠ “distinctWithNull” (preserves null as a distinct value)
• Do not confuse: “limit” with third parameter true (returns first N items) ≠ “limit” with false (returns last N items)
• Do not confuse: “intersect” (common elements between two lists) ≠ “filter” (elements matching specific key values)

FAQ:

• Q: How do I get the first 3 items of a list? — Use limit(myList, 3) or limit(myList, 3, true); the default is to return the first items.
• Q: How do I get the last 3 items of a list? — Use limit(myList, 3, false).
• Q: What is the difference between distinct and distinctWithNull? — distinct ignores null values and excludes them from the result; distinctWithNull treats null as a distinct value and includes one null entry if any nulls are present.
• Q: Can I filter a list of strings with filter? — No, filter only works on listObject; for scalar lists use in or distinct for deduplication.
• Q: How do I check if a value is in a list? — Use in(value, myList), which returns true if the value is found in the list.
• Q: Can I sort a listObject by a specific attribute? — Yes, use sort(@event{...}, "attributeName", true) where the second parameter is the attribute name and the third is the sort direction (true = ascending).