This is the new *CloudFormation Template Reference Guide*. Please update your bookmarks and links. For help getting started with CloudFormation, see the [AWS CloudFormation User Guide](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/Welcome.html).

# `Fn::FindInMap enhancements`
<a name="intrinsic-function-reference-findinmap-enhancements"></a>

The `AWS::LanguageExtensions` transform enhances the functionality of the `Fn::FindInMap` intrinsic function in CloudFormation templates.

The `Fn::FindInMap` function is used to retrieve a value from a mapping defined in the `Mappings` section of a CloudFormation template. However, the standard `Fn::FindInMap` function has limitations, such as the inability to handle missing mappings or use a `Fn::FindInMap` function with some intrinsic functions embedded inside it.

The `AWS::LanguageExtensions` transform addresses these limitations by introducing the following enhancements:
+ **Default value support** – You can specify a default value to be returned if a mapping is not found.
+ **Intrinsic function support** – You can also use a wider range of intrinsic functions to define the fields of `Fn::FindInMap` than with the standard `Fn::FindInMap` function.

## Declaration
<a name="intrinsic-function-reference-findinmap-enhancements-declaration"></a>

### JSON
<a name="intrinsic-function-reference-findinmap-enhancements-syntax.json"></a>

```
{ "Fn::FindInMap" : [
    "MapName",
    "TopLevelKey",
    "SecondLevelKey",
    {"DefaultValue": "DefaultValue"}
  ]
}
```

### YAML
<a name="intrinsic-function-reference-findinmap-enhancements-syntax.yaml"></a>

Syntax for the full function name:

```
Fn::FindInMap:
  - MapName
  - TopLevelKey
  - SecondLevelKey
  - DefaultValue: DefaultValue
```

Syntax for the short form:

```
!FindInMap
  - MapName
  - TopLevelKey
  - SecondLevelKey
  - DefaultValue: DefaultValue
```

## Parameters
<a name="intrinsic-function-reference-findinmap-enhancements-parameters"></a>

DefaultValue  <a name="DefaultValue"></a>
The value that `Fn::FindInMap` will resolve to if the `TopLevelKey` and/or `SecondLevelKey` can not be found from the `MapName` map. This field is optional.

All parameters `MapName`, `TopLevelKey`, `SecondLevelKey`, and `DefaultValue` can be an intrinsic function as long as it's able to resolve to a valid value during the transform.

## Examples
<a name="w2aac28c16c20c15"></a>

The following examples demonstrate how to define the fields of `Fn::FindInMap` when you add the `AWS::LanguageExtensions` transform.

### Using a default value
<a name="intrinsic-function-reference-findinmap-enhancements-example"></a>

The following is an example of using a default value in the `Fn::FindInMap` function.

#### JSON
<a name="intrinsic-function-reference-findinmap-default-value-example.json"></a>

```
{
  //...
    "Transform": "AWS::LanguageExtensions",
    //...
    "Fn::FindInMap": [
      "RegionMap",
      { "Ref": "AWS::Region" },
      "InstanceType",
      { "DefaultValue": "t3.micro" }
    ]
  //...
}
```

#### YAML
<a name="intrinsic-function-reference-findinmap-default-value-example.yaml"></a>

```
Transform: 'AWS::LanguageExtensions'
#...
    !FindInMap 
        - 'RegionMap'
        - !Ref 'AWS::Region'
        - 'InstanceType'
        - DefaultValue: t3.micro
#...
```

#### Using intrinsic functions to define the top level key
<a name="intrinsic-function-reference-findinmap-enhancements-example"></a>

The following is an example of using a `Fn::FindInMap` function with the `Fn::Select` and `Fn::Split` intrinsic functions embedded inside it to define the top level key.

##### JSON
<a name="intrinsic-function-reference-findinmap-enhancement-example.json"></a>

```
{
  //...
  "Transform": "AWS::LanguageExtensions",
  //...
      "Fn::FindInMap": [
        "MyMap",
        {
          "Fn::Select": [
            0,
            {
              "Fn::Split": [
                "|",
                { "Ref": "InputKeys" }
              ]
            }
          ]
        },
        "SecondKey"
      ]
//...
}
```

##### YAML
<a name="intrinsic-function-reference-findinmap-enhance-example.yaml"></a>

```
Transform: 'AWS::LanguageExtensions'
#...
    !FindInMap: [MyMap, !Select [0, !Split [|, !Ref InputKeys]], SecondKey]
#...
```

## Supported functions
<a name="intrinsic-function-reference-findinmap-enhancements-supported-functions"></a>

You can use the following functions in the parameters of `Fn::FindInMap:` enhancements:
+ ``Fn::FindInMap``
+ ``Fn::Join``
+ ``Fn::Sub``
+ ``Fn::If``
+ ``Fn::Select``
+ ``Fn::Length``
+ ``Fn::ToJsonString``
+ ``Fn::Split`` - Unless it’s used for the default value, `Fn::Split` has to be used in conjunction with intrinsic functions that produce a string, such as ``Fn::Join`` or ``Fn::Select``.
+ ``Ref``

## Related resources
<a name="w2aac28c16c20c19"></a>

For more information and examples that show how to use the `Fn::FindInMap` intrinsic function, see [`Fn::FindInMap`](intrinsic-function-reference-findinmap.md).

For more information about the `AWS::LanguageExtensions` transform, see [`AWS::LanguageExtensions` transform](transform-aws-languageextensions.md).