--- schema_version: "1" id: 6110fb7ba319300e52df760582d0e685ae3e8c9260e2a0d73bff20516177355d title: Core (dw::Core) collection: mulesoft version: current locale: en-us portal_url: https://docs.salesforce.com/mulesoft/current/en-us/dataweave/2.6/dw-core.md canonical_url: https://docs.mulesoft.com/dataweave/2.6/dw-core source_site: docs.mulesoft.com content_type: documentation content_hash: 0778749269aba09b3e3ceae13c0de0dab6bd03b30740daeede608bb28a9b4e52 description: MuleSoft Documentation Site release: "2.6" latest: false --- --- product: DataWeave version: 2.6 --- # Core (dw::Core) > For the full documentation index, see: https://docs.mulesoft.com/llms.txt This module contains core DataWeave functions for data transformations. It is automatically imported into any DataWeave script. ## Functions

Name	Description
++	Concatenates two values.
--	Removes specified values from an input value.
abs	Returns the absolute value of a number.
avg	Returns the average of numbers listed in an array.
ceil	Rounds a number up to the nearest whole number.
contains	Returns `true` if an input contains a given value, `false` if not.
daysBetween	Returns the number of days between two dates.
distinctBy	Iterates over the input and returns the unique elements in it.
endsWith	Returns `true` if a string ends with a provided substring, `false` if not.
entriesOf	Returns an array of key-value pairs that describe the key, value, and any attributes in the input object.
evaluateCompatibilityFlag	Returns the value of the compatibility flag with the specified name.
filter	Iterates over an array and applies an expression that returns matching values.
filterObject	Iterates a list of key-value pairs in an object and applies an expression that returns only matching objects, filtering out the rest from the output.
find	Returns indices of an input that match a specified value.
flatMap	Iterates over each item in an array and flattens the results.
flatten	Turns a set of subarrays (such as `[ [1,2,3], [4,5,[6]], [], [null] ]`) into a single, flattened array (such as `[ 1, 2, 3, 4, 5, [6], null ]`).
floor	Rounds a number down to the nearest whole number.
groupBy	Returns an object that groups items from an array based on specified criteria, such as an expression or matching selector.
indexOf	Returns the index of the first occurrence of the specified element in this array, or `-1` if this list does not contain the element.
isBlank	Returns `true` if the given string is empty (`""`), completely composed of whitespaces, or `null`. Otherwise, the function returns `false`.
isDecimal	Returns `true` if the given number contains a decimal, `false` if not.
isEmpty	Returns `true` if the given input value is empty, `false` if not.
isEven	Returns `true` if the number or numeric result of a mathematical operation is even, `false` if not.
isInteger	Returns `true` if the given number is an integer (which lacks decimals), `false` if not.
isLeapYear	Returns `true` if it receives a date for a leap year, `false` if not.
isOdd	Returns `true` if the number or numeric result of a mathematical operation is odd, `false` if not.
joinBy	Merges an array into a single string value and uses the provided string as a separator between each item in the list.
keysOf	Returns an array of keys from key-value pairs within the input object.
lastIndexOf	Returns the index of the last occurrence of the specified element in a given array or `-1` if the array does not contain the element.
log	Without changing the value of the input, `log` returns the input as a system log. So this makes it very simple to debug your code, because any expression or subexpression can be wrapped with log and the result will be printed out without modifying the result of the expression. The output is going to be printed in application/dw format.
lower	Returns the provided string in lowercase characters.
map	Iterates over items in an array and outputs the results into a new array.
mapObject	Iterates over an object using a mapper that acts on keys, values, or indices of that object.
match	Uses a Java regular expression (regex) to match a string and then separates it into capture groups. Returns the results in an array.
matches	Checks if an expression matches the entire input string.
max	Returns the highest `Comparable` value in an array.
maxBy	Iterates over an array and returns the highest value of `Comparable` elements from it.
min	Returns the lowest `Comparable` value in an array.
minBy	Iterates over an array to return the lowest value of comparable elements from it.
mod	Returns the modulo (the remainder after dividing the `dividend` by the `divisor`).
namesOf	Returns an array of strings with the names of all the keys within the given object.
now	Returns a `DateTime` value for the current date and time.
onNull	Executes a callback function if the preceding expression returns a `null` value and then replaces the `null` value with the result of the callback.
orderBy	Reorders the elements of an input using criteria that acts on selected elements of that input.
pluck	Useful for mapping an object into an array, `pluck` iterates over an object and returns an array of keys, values, or indices from the object.
pow	Raises the value of a `base` number to the specified `power`.
random	Returns a pseudo-random number greater than or equal to `0.0` and less than `1.0`.
randomInt	Returns a pseudo-random whole number from `0` to the specified number (exclusive).
read	Reads a string or binary and returns parsed content.
readUrl	Reads a URL, including a classpath-based URL, and returns parsed content. This function works similar to the `read` function.
reduce	Applies a reduction expression to the elements in an array.
replace	Performs string replacement.
round	Rounds a number up or down to the nearest whole number.
scan	Returns an array with all of the matches found in an input string.
sizeOf	Returns the number of elements in an array. It returns `0` if the array is empty.
splitBy	Splits a string into a string array based on a value that matches part of that string. It filters out the matching part from the returned array.
sqrt	Returns the square root of a number.
startsWith	Returns `true` or `false` depending on whether the input string starts with a matching prefix.
sum	Returns the sum of numeric values in an array.
then	This function works as a pipe that passes the value returned from the preceding expression to the next (a callback) only if the value returned by the preceding expression is not `null`.
to	Returns a range with the specified boundaries.
trim	Removes any blank spaces from the beginning and end of a string.
typeOf	Returns the primitive data type of a value, such as `String`.
unzip	Performs the opposite of `zip`. It takes an array of arrays as input.
upper	Returns the provided string in uppercase characters.
uuid	Returns a v4 UUID using random numbers as the source.
valuesOf	Returns an array of the values from key-value pairs in an object.
with	Helper function that specifies a replacement element. This function is used with `replace`, `update` or `mask` to perform data substitutions.
write	Writes a value as a string or binary in a supported format.
xsiType	Creates a `xsi:type` type attribute. This method returns an object, so it must be used with dynamic attributes.
zip	Merges elements from two arrays into an array of arrays.

## Types - [Core Types](https://docs.mulesoft.com/dataweave/2.6/dw-core-types) ## Namespaces - [Core Namespaces](https://docs.mulesoft.com/dataweave/2.6/dw-core-namespaces) ## Annotations - [Core Annotations](https://docs.mulesoft.com/dataweave/2.6/dw-core-annotations)