Map

Map( array, lambda )
Map( array, lambda )
Map( array, lambda )
Map( array, lambda )
map_expr( lambda, array )
map array  lambda
Map( array, lambda )
Map( array, lambda )

Description

The Map function applies a Lambda serially to each member of the array and returns the results of each application in a new array of the same type. Later invocations of the Lambda function can see the results of earlier invocations.

Parameters

Argument Type Definition and Requirements

array

Array

The target array over which the lambda function iterates/operates.

lambda

Lambda

The anonymous function to be executed.

Returns

A new array with the results of the Lambda for the given array.

Examples

The query below has a Lambda which takes one variable x and adds 1 and then returns the value. This Lambda is executed once for each value in the array. These values are 1, 2, 3.

curl https://db.fauna.com/ \
    -u fnAChGwBcAACAO70ziE0cfROosNJHdgBmJU1PgpL: \
    -d '{
          "map": { "lambda": "x", "expr": { "add": [ { "var": "x" }, 1 ] } },
          "collection": [ 1, 2, 3 ]
        }'
client.Query(Map(Arr(1, 2, 3), x => Add(x, 1)));
System.out.println(
  client.query(
    Map(
       Arr(Value(1), Value(2), Value(3)),
       Lambda(Value("x"), Add(Var("x"), Value(1)))
    )
  ).get());
result, _ := client.Query(
    f.Map(f.Arr{1, 2, 3}, f.Lambda("x", f.Add(f.Var("x"), 1))),
)

fmt.Println(result)
client.query(Map(Arr(1, 2, 3), Lambda { x => Add(x, 1) }))
client.query(q.map_expr(lambda x: q.add(x, 1), [1, 2, 3]))
$client.query do
  map [1, 2, 3] do |x|
    add(x, 1)
  end
end
client.query(
    Map(collection: Arr(1, 2, 3), to: { x in Add(x, 1) })
)
client.query(
  q.Map([1, 2, 3], q.Lambda('x', q.Add(q.Var('x'), 1)))
)
.then((ret) => console.log(ret))
HTTP/1.1 200 OK
{ "resource": [ 2, 3, 4 ] }
[ 2, 3, 4 ]
[2, 3, 4]
[2 3 4]
[ 2, 3, 4 ]
[ 2, 3, 4 ]
[ 2, 3, 4 ]
[ 2, 3, 4 ]
[ 2, 3, 4 ]

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