For Each (map)

Applies a mapper function to each event in a stream and returns a record. Use this function to edit an existing field, like a field in attributes. You can also use For Each to put a new field in a map object, like attributes as well. The API function name of For Each is map.

Function Input

collection<record<R>>

This function takes in collections of records with schema R.

Function Output

collection<record<S>>

This function outputs the same collection of records but with a different schema S.

Arguments

Argument	Input	Description	UI example
mapper	expression<record<S>>	Applies a mapper scalar function to each record. Unlike Eval, the For Each function is not variadic and only accepts one mapper scalar function as an argument. If you put more than one mapper function, an error is thrown.	map-put("attributes", "index", "metrics");

DSL example

In a map object field, like attributes, set the key "index" to value "metrics":

map(input, map-put("attributes", "index", "metrics"));