--- schema_version: "1" id: 21936c18c3a17381d18683c3c45ec91f94ec7097018e44e88c76b33189813464 title: Arrays (dw::core::Arrays) collection: mulesoft version: current locale: en-us portal_url: https://docs.salesforce.com/mulesoft/current/en-us/dataweave/2.3/dw-arrays.md canonical_url: https://docs.mulesoft.com/dataweave/2.3/dw-arrays source_site: docs.mulesoft.com content_type: documentation content_hash: 49ba92792d1e086e974652ea32e643346f08c00dc0d9439c0011a7f33a8dd566 description: MuleSoft Documentation Site release: "2.3" latest: false --- --- product: DataWeave version: 2.3 --- # Arrays (dw::core::Arrays) > For the full documentation index, see: https://docs.mulesoft.com/llms.txt This module contains helper functions for working with arrays. To use this module, you must import it to your DataWeave code, for example, by adding the line `import * from dw::core::Arrays` to the header of your DataWeave script. ## Functions

Name	Description
countBy	Counts the elements in an array that match the results of a function.
divideBy	Breaks up an array into sub-arrays that contain the specified number of elements.
drop	Drops the first `n` elements. It returns the original array when `n <= 0` and an empty array when `n > sizeOf(array)`.
dropWhile	Drops elements from the array while the condition is met but stops the selection process when it reaches an element that fails to satisfy the condition.
every	Returns `true` if every element in the array matches the condition.
firstWith	Returns the first element that satisfies the condition, or returns `null` if no element meets the condition.
indexOf	Returns the index of the first occurrence of an element within the array.
indexWhere	Returns the index of the first occurrence of an element that matches a condition within the array.
join	Joins two arrays of objects by a given ID criteria.
leftJoin	Joins two arrays of objects by a given ID criteria.
outerJoin	Joins two array of objects by a given `ID` criteria.
partition	Separates the array into the elements that satisfy the condition from those that do not.
slice	Selects the interval of elements that satisfy the condition: `from <= indexOf(array) < until`
some	Returns `true` if at least one element in the array matches the specified condition.
splitAt	Splits an array into two at a given position.
splitWhere	Splits an array into two at the first position where the condition is met.
sumBy	Returns the sum of the values of the elements in an array.
take	Selects the first `n` elements. It returns an empty array when `n <= 0` and the original array when `n > sizeOf(array)`.
takeWhile	Selects elements from the array while the condition is met but stops the selection process when it reaches an element that fails to satisfy the condition.