> ## Documentation Index
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# DA.TextMap

> Reference documentation for Daml module DA.TextMap.

<span id="module-da-textmap-81719" />

# DA.TextMap

TextMap - A map is an associative array data type composed of a

collection of key/value pairs such that, each possible key appears

at most once in the collection.

## Module Snapshot

<CardGroup cols={2}>
  <Card title="Lifecycle">
    Stable.
  </Card>

  <Card title="Notices">
    Status: `active`
    Introduced in: `3.4.9`
    Removed in: `-`
    Warnings: `0`
    Deprecations: `0`
    Deprecated since: `-`
  </Card>
</CardGroup>

## Functions

<span id="function-da-textmap-fromlist-19033" />

### `fromList`

`fromList` : \[([`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952), `a`)] -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a`

Create a map from a list of key/value pairs.

<span id="function-da-textmap-fromlistwithl-22912" />

### `fromListWithL`

`fromListWithL` : (`a` -> `a` -> `a`) -> \[([`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952), `a`)] -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a`

Create a map from a list of key/value pairs with a combining
function. The combining function is only used when a key appears multiple
times in the list and it takes two arguments: the first one is the new value
being inserted at that key and the second one is the value accumulated so
far at that key.
Examples:

```
>>> fromListWithL (++) [("A", [1]), ("A", [2]), ("B", [2]), ("B", [1]), ("A", [3])]
fromList [("A", [3, 2, 1]), ("B", [1, 2])]
>>> fromListWithL (++) [] == (empty : TextMap [Int])
True
```

<span id="function-da-textmap-fromlistwithr-69626" />

### `fromListWithR`

`fromListWithR` : (`a` -> `a` -> `a`) -> \[([`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952), `a`)] -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a`

Create a map from a list of key/value pairs like `fromListWithL`
with the combining function flipped. Examples:

```
>>> fromListWithR (++) [("A", [1]), ("A", [2]), ("B", [2]), ("B", [1]), ("A", [3])]
fromList [("A", [1, 2, 3]), ("B", [2, 1])]
>>> fromListWithR (++) [] == (empty : TextMap [Int])
True
```

<span id="function-da-textmap-fromlistwith-41741" />

### `fromListWith`

`fromListWith` : (`a` -> `a` -> `a`) -> \[([`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952), `a`)] -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a`

<span id="function-da-textmap-tolist-95168" />

### `toList`

`toList` : [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a` -> \[([`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952), `a`)]

Convert the map to a list of key/value pairs where the keys are
in ascending order.

<span id="function-da-textmap-empty-66187" />

### `empty`

`empty` : [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a`

The empty map.

<span id="function-da-textmap-size-46150" />

### `size`

`size` : [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a` -> [`Int`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-int-37261)

Number of elements in the map.

<span id="function-da-textmap-null-64690" />

### `null`

`null` : [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `v` -> [`Bool`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-bool-66265)

Is the map empty?

<span id="function-da-textmap-lookup-87021" />

### `lookup`

`lookup` : [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952) -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a` -> [`Optional`](/appdev/reference/daml-standard-library/prelude#type-da-internal-prelude-optional-37153) `a`

Lookup the value at a key in the map.

<span id="function-da-textmap-member-14417" />

### `member`

`member` : [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952) -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `v` -> [`Bool`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-bool-66265)

Is the key a member of the map?

<span id="function-da-textmap-filter-317" />

### `filter`

`filter` : (`v` -> [`Bool`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-bool-66265)) -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `v` -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `v`

Filter the `TextMap` using a predicate: keep only the entries where the
value satisfies the predicate.

<span id="function-da-textmap-filterwithkey-64027" />

### `filterWithKey`

`filterWithKey` : ([`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952) -> `v` -> [`Bool`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-bool-66265)) -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `v` -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `v`

Filter the `TextMap` using a predicate: keep only the entries which
satisfy the predicate.

<span id="function-da-textmap-delete-54270" />

### `delete`

`delete` : [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952) -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a` -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a`

Delete a key and its value from the map. When the key is not a
member of the map, the original map is returned.

<span id="function-da-textmap-singleton-39431" />

### `singleton`

`singleton` : [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952) -> `a` -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a`

Create a singleton map.

<span id="function-da-textmap-insert-41312" />

### `insert`

`insert` : [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952) -> `a` -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a` -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a`

Insert a new key/value pair in the map. If the key is already
present in the map, the associated value is replaced with the
supplied value.

<span id="function-da-textmap-insertwith-45464" />

### `insertWith`

`insertWith` : (`v` -> `v` -> `v`) -> [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952) -> `v` -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `v` -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `v`

Insert a new key/value pair in the map. If the key is already
present in the map, it is combined with the previous value using the given function
`f new_value old_value`.

<span id="function-da-textmap-union-13945" />

### `union`

`union` : [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a` -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a` -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a`

The union of two maps, preferring the first map when equal
keys are encountered.

<span id="function-da-textmap-merge-26784" />

### `merge`

`merge` : ([`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952) -> `a` -> [`Optional`](/appdev/reference/daml-standard-library/prelude#type-da-internal-prelude-optional-37153) `c`) -> ([`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952) -> `b` -> [`Optional`](/appdev/reference/daml-standard-library/prelude#type-da-internal-prelude-optional-37153) `c`) -> ([`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952) -> `a` -> `b` -> [`Optional`](/appdev/reference/daml-standard-library/prelude#type-da-internal-prelude-optional-37153) `c`) -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a` -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `b` -> [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `c`

Merge two maps. `merge f g h x y` applies `f` to all key/value pairs
whose key only appears in `x`, `g` to all pairs whose key only appears
in `y` and `h` to all pairs whose key appears in both `x` and `y`.
In the end, all pairs yielding `Some` are collected as the result.

## Orphan Typeclass Instances

* instance [`Show`](/appdev/reference/daml-standard-library/prelude#class-ghc-show-show-65360) `a` => [`Show`](/appdev/reference/daml-standard-library/prelude#class-ghc-show-show-65360) ([`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a`)

* instance [`Eq`](/appdev/reference/daml-standard-library/prelude#class-ghc-classes-eq-22713) `a` => [`Eq`](/appdev/reference/daml-standard-library/prelude#class-ghc-classes-eq-22713) ([`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a`)

* instance [`Ord`](/appdev/reference/daml-standard-library/prelude#class-ghc-classes-ord-6395) `a` => [`Ord`](/appdev/reference/daml-standard-library/prelude#class-ghc-classes-ord-6395) ([`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `a`)

* instance [`Semigroup`](/appdev/reference/daml-standard-library/prelude#class-da-internal-prelude-semigroup-78998) ([`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `b`)

* instance [`Monoid`](/appdev/reference/daml-standard-library/prelude#class-da-internal-prelude-monoid-6742) ([`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691) `b`)

* instance [`Functor`](/appdev/reference/daml-standard-library/prelude#class-ghc-base-functor-31205) [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691)

* instance [`Foldable`](/appdev/reference/daml-standard-library/da-foldable#class-da-foldable-foldable-25994) [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691)

* instance [`Traversable`](/appdev/reference/daml-standard-library/da-traversable#class-da-traversable-traversable-18144) [`TextMap`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-textmap-11691)