github.com/muratcelep/terraform@v1.1.0-beta2-not-internal-4/website/docs/language/functions/lookup.html.md (about)

     1  ---
     2  layout: "language"
     3  page_title: "lookup - Functions - Configuration Language"
     4  sidebar_current: "docs-funcs-collection-lookup"
     5  description: |-
     6    The lookup function retrieves an element value from a map given its key.
     7  ---
     8  
     9  # `lookup` Function
    10  
    11  `lookup` retrieves the value of a single element from a map, given its key.
    12  If the given key does not exist, the given default value is returned instead.
    13  
    14  ```
    15  lookup(map, key, default)
    16  ```
    17  
    18  -> For historical reasons, the `default` parameter is actually optional. However,
    19  omitting `default` is deprecated since v0.7 because that would then be
    20  equivalent to the native index syntax, `map[key]`.
    21  
    22  ## Examples
    23  
    24  ```
    25  > lookup({a="ay", b="bee"}, "a", "what?")
    26  ay
    27  > lookup({a="ay", b="bee"}, "c", "what?")
    28  what?
    29  ```
    30  
    31  ## Related Functions
    32  
    33  * [`element`](./element.html) retrieves a value from a _list_ given its _index_.