coll.frequencies

Description

Counts the frequency of each element in a list, returning a map where keys are the unique elements and values are their occurrence counts.

Syntax 

flex.coll.frequencies(list)

Parameters

| Parameter | Type | Required | Description | |———–|——|———-|————-| | list | list | Yes | The list to analyze |

Returns

Type: map (object)

A map where each key is a unique element from the list and each value is the count of how many times that element appears. Returns an empty map if input is not an array.

Examples

Example 1: Basic Frequency Count 

WITH ['apple', 'banana', 'apple', 'cherry', 'banana', 'apple'] AS fruits
RETURN flex.coll.frequencies(fruits) AS counts

Output:

counts
---------------------------------------
{apple: 3, banana: 2, cherry: 1}

Example 2: Tag Analysis 

MATCH (d:Document)
WITH collect(d.tags) AS allTagLists
UNWIND allTagLists AS tags
UNWIND tags AS tag
WITH collect(tag) AS flatTags
RETURN flex.coll.frequencies(flatTags) AS tagCounts

Example 3: Finding Most Common Values 

MATCH (u:User)
WITH collect(u.country) AS countries
WITH flex.coll.frequencies(countries) AS freq
UNWIND keys(freq) AS country
RETURN country, freq[country] AS count
ORDER BY count DESC
LIMIT 10

Example 4: Word Frequency Analysis 

MATCH (doc:Document)
WITH split(toLower(doc.content), ' ') AS words
WITH flex.coll.frequencies(words) AS wordCounts
UNWIND keys(wordCounts) AS word
WHERE wordCounts[word] > 5
RETURN word, wordCounts[word] AS frequency
ORDER BY frequency DESC

Notes

  • Returns empty map if input is not an array or is null
  • null and undefined values are stored with key "null"
  • All elements are converted to string keys in the result map
  • Useful for analytics, statistics, and data exploration
  • Can be combined with keys() and sorting for top-N analysis

See Also