Array

Utilities for working with arrays.

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import Array from "array"

Values

Functions for working with the Array data type.

Array.length

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length : Array<a> -> Number

Provides the length of the input array.

Parameters:

Returns:

Examples:

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Array.length([> 1, 2, 3, 4, 5]) == 5

Array.make

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make : (Number, a) -> Array<a>

Creates a new array of the specified length with each element being initialized with the given value.

Parameters:

Returns:

Throws:

InvalidArgument(String)

• When length is not an integer
• When length is negative

Examples:

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Array.make(5, "foo") // [> "foo", "foo", "foo", "foo", "foo"]

Array.init

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init : (Number, (Number -> a)) -> Array<a>

Creates a new array of the specified length where each element is initialized with the result of an initializer function. The initializer is called with the index of each array element.

Parameters:

Returns:

Throws:

InvalidArgument(String)

• When length is not an integer
• When length is negative

Examples:

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Array.init(5, n => n + 3) // [> 3, 4, 5, 6, 7]

Array.get

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get : (Number, Array<a>) -> a

An alias for normal syntactic array access, i.e. array[n].

Retrieves the element from the array at the specified index. A negative index is treated as an offset from the end of the array.

Parameters:

Returns:

Examples:

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Array.get(1,[> 1, 2, 3, 4, 5]) == 2

Array.set

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set : (Number, a, Array<a>) -> Void

An alias for normal syntactic array set, i.e. array[n] = value.

Sets the element at the specified index in the array to the new value. A negative index is treated as an offset from the end of the array.

Parameters:

Examples:

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Array.set(1, 9, [> 1, 2, 3, 4, 5]) == [> 1, 9, 3, 4, 5]

Array.append

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append : (Array<a>, Array<a>) -> Array<a>

Creates a new array with the elements of the first array followed by the elements of the second array. This does not modify the arguments.

Parameters:

Returns:

Examples:

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Array.append([> 1, 2], [> 3, 4, 5]) == [> 1, 2, 3, 4, 5]

Array.concat

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concat : List<Array<a>> -> Array<a>

Creates a single array containing the elements of all arrays in the provided list. Does not modify any of the input arguments.

Parameters:

Returns:

Examples:

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Array.concat([[> 1, 2], [> 3, 4], [> 5, 6]]) == [> 1, 2, 3, 4, 5, 6]

Array.copy

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copy : Array<a> -> Array<a>

Produces a shallow copy of the input array. The new array contains the same elements as the original.

Parameters:

Returns:

Array.cycle

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cycle : ((a -> Void), Number, Array<a>) -> Void

Iterates an array a given number of times, calling an iterator function on each element.

Parameters:

Array.forEach

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forEach : ((a -> Void), Array<a>) -> Void

Iterates an array, calling an iterator function on each element.

Parameters:

Array.forEachi

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forEachi : (((a, Number) -> Void), Array<a>) -> Void

Iterates an array, calling an iterator function on each element. Also passes the index as the second argument to the function.

Parameters:

Array.map

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map : ((a -> b), Array<a>) -> Array<b>

Produces a new array initialized with the results of a mapper function called on each element of the input array.

Parameters:

Returns:

Array.mapi

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mapi : (((a, Number) -> b), Array<a>) -> Array<b>

Produces a new array initialized with the results of a mapper function called on each element of the input array and its index.

Parameters:

Returns:

Array.reduce

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reduce : (((a, b) -> a), a, Array<b>) -> a

Combines all elements of an array using a reducer function, starting from the “head”, or left side, of the array.

In Array.reduce(fn, initial, array), fn is called with an accumulator and each element of the array, and returns a new accumulator. The final value is the last accumulator returned. The accumulator starts with value initial.

Parameters:

Returns:

Examples:

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Array.reduce((a, b) => a + b, 0, [> 1, 2, 3]) // 6

Array.reduceRight

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reduceRight : (((a, b) -> b), b, Array<a>) -> b

Combines all elements of an array using a reducer function, starting from the “end”, or right side, of the array.

In Array.reduceRight(fn, initial, array), fn is called with each element of the array and an accumulator, and returns a new accumulator. The final value is the last accumulator returned. The accumulator starts with value initial.

Parameters:

Returns:

Examples:

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Array.reduceRight((a, b) => b ++ a, "", [> "baz", "bar", "foo"]) // "foobarbaz"

Array.reducei

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reducei : (((a, b, Number) -> a), a, Array<b>) -> a

Combines all elements of an array using a reducer function, starting from the “head”, or left side, of the array.

In Array.reducei(fn, initial, array), fn is called with an accumulator, each element of the array, and the index of that element, and returns a new accumulator. The final value is the last accumulator returned. The accumulator starts with value initial.

Parameters:

Returns:

Array.flatMap

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flatMap : ((b -> Array<a>), Array<b>) -> Array<a>

Produces a new array by calling a function on each element of the input array. Each iteration produces an intermediate array, which are all appended to produce a “flattened” array of all results.

Parameters:

Returns:

Array.every

1

every : ((a -> Bool), Array<a>) -> Bool

Checks that the given condition is satisfied for all elements in the input array.

Parameters:

Returns:

Array.some

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some : ((a -> Bool), Array<a>) -> Bool

Checks that the given condition is satisfied at least once by an element in the input array.

Parameters:

Returns:

Array.fill

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fill : (a, Array<a>) -> Void

Replaces all elements in an array with the new value provided.

Parameters:

Array.fillRange

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fillRange : (a, Number, Number, Array<a>) -> Void

Replaces all elements in the provided index range in the array with the new value provided. Fails if the index is out-of-bounds.

Parameters:

Array.reverse

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reverse : Array<a> -> Array<a>

Creates a new array with all elements in reverse order.

Parameters:

Returns:

Array.toList

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toList : Array<a> -> List<a>

Converts the input array to a list.

Parameters:

Returns:

Array.fromList

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fromList : List<a> -> Array<a>

Converts the input list to an array.

Parameters:

Returns:

Array.contains

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contains : (a, Array<a>) -> Bool

Checks if the value is an element of the input array. Uses the generic == structural equality operator.

Parameters:

Returns:

Array.find

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find : ((a -> Bool), Array<a>) -> Option<a>

Finds the first element in an array that satifies the given condition.

Parameters:

Returns:

Array.findIndex

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findIndex : ((a -> Bool), Array<a>) -> Option<Number>

Finds the first index in an array where the element satifies the given condition.

Parameters:

Returns:

Array.product

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product : (Array<a>, Array<b>) -> Array<(a, b)>

Combines two arrays into a Cartesian product of tuples containing all ordered pairs (a, b).

Parameters:

Returns:

Array.count

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count : ((a -> Bool), Array<a>) -> Number

Counts the number of elements in an array that satisfy the given condition.

Parameters:

Returns:

Array.counti

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counti : (((a, Number) -> Bool), Array<a>) -> Number

Counts the number of elements in an array that satisfy the given condition. Also passes the index to the function.

Parameters:

Returns:

Array.filter

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filter : ((a -> Bool), Array<a>) -> Array<a>

Produces a new array by calling a function on each element of the input array and only including it in the result array if the element satisfies the condition.

Parameters:

Returns:

Array.filteri

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filteri : (((a, Number) -> Bool), Array<a>) -> Array<a>

Produces a new array by calling a function on each element of the input array and only including it in the result array if the element satisfies the condition. Also passes the index to the function.

Parameters:

Returns:

Array.unique

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unique : Array<a> -> Array<a>

Produces a new array with any duplicates removed. Uses the generic == structural equality operator.

Parameters:

Returns:

Array.zip

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zip : (Array<a>, Array<b>) -> Array<(a, b)>

Produces a new array filled with tuples of elements from both given arrays. The first tuple will contain the first item of each array, the second tuple will contain the second item of each array, and so on.

Parameters:

Returns:

Throws:

Failure(String)

• When the arrays have different sizes

Array.zipWith

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zipWith : (((a, b) -> c), Array<a>, Array<b>) -> Array<c>

Produces a new array filled with elements defined by applying a function on pairs from both given arrays. The first element will contain the result of applying the function to the first elements of each array, the second element will contain the result of applying the function to the second elements of each array, and so on.

Calling this function with arrays of different sizes will cause the returned array to have the length of the smaller array.

Parameters:

Returns:

Examples:

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Array.zipWith((a, b) => a + b, [> 1, 2, 3], [> 4, 5, 6]) // [> 5, 7, 9]

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Array.zipWith((a, b) => a * b, [> 1, 2, 3], [> 4, 5]) // [> 4, 10]

Array.unzip

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unzip : Array<(a, b)> -> (Array<a>, Array<b>)

Produces two arrays by splitting apart an array of tuples.

Parameters:

Returns:

Array.join

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join : (String, Array<String>) -> String

Concatenates an array of strings into a single string, separated by a separator string.

Parameters:

Returns:

Array.slice

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slice : (Number, Number, Array<a>) -> Array<a>

Slices an array given zero-based start and end indexes. The value at the end index will not be included in the result.

If either index is a negative number, it will be treated as a reverse index from the end of the array. e.g. slice(1, -1, [> 'a', 'b', 'c']) == [> 'b'].

Parameters:

Returns:

Array.sort

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sort : (((a, a) -> Number), Array<a>) -> Void

Sorts an array in-place.

Ordering is calculated using a comparator function which takes two array elements and must return 0 if both are equal, a positive number if the first is greater, and a negative number if the first is smaller.

Parameters:

Array.rotate

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rotate : (Number, Array<a>) -> Void

Rotates array elements by the specified amount to the right, in place.

If value is negative, array elements will be rotated by the specified amount to the left. See examples.

Parameters:

Examples:

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let array = [> 1, 2, 3, 4, 5]; rotate(2, arr); arr == [> 4, 5, 1, 2, 3]

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let array = [> 1, 2, 3, 4, 5]; rotate(-1, arr); arr == [> 2, 3, 4, 5, 1]