a!map() Function

Function

a!map( key1, keyN )

Creates a map of values (Any Type) with each value stored at the corresponding string key. Values stored in maps are not wrapped in variants.

See also: Appian Data Types

Parameters

Returns

Map

Usage consideration

Function requirements

• Keywords must be unique.
• Keywords are not case sensitive.

Maps vs. dictionaries

While similar to a dictionary, which uses curly braces {}, the values stored in a map are not wrapped in variants. This makes it much easier to get values back out of maps by indexing, without having to worry about type casting. There are no advantages to using dictionaries; prefer using maps over dictionaries where possible.

Casting a map

• A map can be cast to a dictionary, CDT, record, or text.
• A dictionary, CDT, or record can be cast to a map.

Examples

Create a single map

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a!map(id: 1, name: "Jane Doe")

Create a list of maps

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{
   a!map(id: 1, name: "Jane Doe"),
   a!map(id: 2, name: "John Doe")
}

Remove items from maps

The remove() function can return a map without the data specified in the index parameter. Use the key name to specify the data to remove.

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a!localVariables(
  local!map: a!map(val1: "A", val2: "B"),
  local!updated: remove(local!map, "val2"),
  local!updated
)

Returns a!map(val1: "A").

The index can also be a list of key names, letting you remove multiple items in one operation.

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a!localVariables(
  local!map: a!map(val1: "A", val2: "B", val3: "C"),
  local!updated: remove(local!map, {"val2", "val1"}),
  local!updated
)

Returns a!map(val3: "C").

To remove items from a list of maps, iterate over the list with a!forEach().

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a!localVariables(
  local!maps: {
    a!map(id: 1, name: "Jane Doe"),
    a!map(id: 2, name: "John Doe")
  },
  local!updated: a!forEach(
    items: local!map,
    expression: remove(fv!item, "id")
  ),
  local!updated
)

Returns {a!map(name: "Jane Doe"), a!map(name: "John Doe")}.

Feature compatibility

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