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Add time and space complexity documentation to Array module functions #18792

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53e62f9
Initial plan
Copilot Jul 30, 2025
77f6cab
Add complexity documentation for allPairs, append, average, averageBy…
Copilot Jul 30, 2025
14f37e4
Add complexity documentation for 14 more Array functions
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276d6f8
Add complexity documentation for 5 more critical Array functions
Copilot Jul 30, 2025
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117 changes: 114 additions & 3 deletions src/FSharp.Core/array.fsi
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,11 @@ module Array =
///
/// <returns>The resulting array of pairs.</returns>
///
/// <remarks>
/// Time Complexity: O(n*m) where n is the length of array1 and m is the length of array2.
/// Space Complexity: O(n*m) for the resulting array.
/// </remarks>
///
/// <example id="all-pairs-1">
/// <code lang="fsharp">
/// ([| 1; 2 |], [| 3; 4 |]) ||> Array.allPairs
Expand All @@ -46,6 +51,11 @@ module Array =
///
/// <exception cref="T:System.ArgumentNullException">Thrown when either of the input arrays is null.</exception>
///
/// <remarks>
/// Time Complexity: O(n+m) where n is the length of array1 and m is the length of array2.
/// Space Complexity: O(n+m) for the resulting array.
/// </remarks>
///
/// <example id="append-1">
/// <code lang="fsharp">
/// Array.append [| 1; 2 |] [| 3; 4 |]
Expand All @@ -64,6 +74,11 @@ module Array =
///
/// <returns>The average of the elements in the array.</returns>
///
/// <remarks>
/// Time Complexity: O(n) where n is the length of the array.
/// Space Complexity: O(1).
/// </remarks>
///
/// <example id="average-1">
/// <code lang="fsharp">
/// [| 1.0; 2.0; 6.0 |] |> Array.average
Expand Down Expand Up @@ -95,6 +110,11 @@ module Array =
///
/// <exception cref="T:System.ArgumentNullException">Thrown when the input array is null.</exception>
///
/// <remarks>
/// Time Complexity: O(n) where n is the length of the array.
/// Space Complexity: O(1).
/// </remarks>
///
/// <example id="average-by-1">
/// <code lang="fsharp">
/// type Foo = { Bar: float }
Expand Down Expand Up @@ -138,6 +158,8 @@ module Array =
/// let target = [| 0; 1; 2; 3; 4; 5 |]
/// target[3..4] &lt;- source[1..2]
/// </code>
/// Time Complexity: O(count) where count is the number of elements to copy.
/// Space Complexity: O(1).
/// </remarks>
///
/// <exception cref="T:System.ArgumentNullException">Thrown when either of the input arrays is null.</exception>
Expand Down Expand Up @@ -165,6 +187,11 @@ module Array =
///
/// <exception cref="T:System.ArgumentNullException">Thrown when the input array is null.</exception>
///
/// <remarks>
/// Time Complexity: O(n*k) where n is the length of the input array and k is the average length of the arrays returned by the mapping function.
/// Space Complexity: O(n*k) for the resulting array.
/// </remarks>
///
/// <example id="collect-1">
/// <code lang="fsharp">
/// type Foo = { Bar: int array }
Expand Down Expand Up @@ -203,6 +230,11 @@ module Array =
/// <exception cref="T:System.ArgumentNullException">Thrown when either of the input arrays
/// is null.</exception>
///
/// <remarks>
/// Time Complexity: O(min(n,m)) where n and m are the lengths of the arrays, as comparison stops at the first non-zero result.
/// Space Complexity: O(1).
/// </remarks>
///
/// <example id="compare-with-1">
/// <code lang="fsharp">
/// let closerToNextDozen a b =
Expand Down Expand Up @@ -278,6 +310,11 @@ module Array =
///
/// <exception cref="T:System.ArgumentNullException">Thrown when the input sequence is null.</exception>
///
/// <remarks>
/// Time Complexity: O(∑|arrays[i]|) where ∑|arrays[i]| is the sum of lengths of all input arrays.
/// Space Complexity: O(∑|arrays[i]|) for the resulting array.
/// </remarks>
///
/// <example id="concat-1">
/// <code lang="fsharp">
/// let inputs = [ [| 1; 2 |]; [| 3 |]; [| 4; 5 |] ]
Expand All @@ -298,6 +335,11 @@ module Array =
///
/// <exception cref="T:System.ArgumentNullException">Thrown when the input array is null.</exception>
///
/// <remarks>
/// Time Complexity: O(n) where n is the length of the array.
/// Space Complexity: O(1).
/// </remarks>
///
/// <example id="contains-1">
/// <code lang="fsharp">
/// [| 1; 2 |] |> Array.contains 2 // evaluates to true
Expand All @@ -315,6 +357,11 @@ module Array =
///
/// <exception cref="T:System.ArgumentNullException">Thrown when the input array is null.</exception>
///
/// <remarks>
/// Time Complexity: O(n) where n is the length of the array.
/// Space Complexity: O(n) for the new array.
/// </remarks>
///
/// <example id="copy-1">
/// <code lang="fsharp">
/// let source = [| 12; 13; 14 |]
Expand All @@ -337,6 +384,11 @@ module Array =
///
/// <exception cref="T:System.ArgumentNullException">Thrown when the input array is null.</exception>
///
/// <remarks>
/// Time Complexity: O(n) where n is the length of the array.
/// Space Complexity: O(k) where k is the number of unique keys.
/// </remarks>
///
/// <example id="count-by-1">
/// <code lang="fsharp">
/// type Foo = { Bar: string }
Expand All @@ -359,6 +411,11 @@ module Array =
///
/// <exception cref="T:System.ArgumentException">Thrown when count is negative.</exception>
///
/// <remarks>
/// Time Complexity: O(n) where n is the count.
/// Space Complexity: O(n) for the new array.
/// </remarks>
///
/// <example id="create-1">
/// <code lang="fsharp">
/// Array.create 4 "a"
Expand Down Expand Up @@ -389,6 +446,11 @@ module Array =
///
/// <returns>The first element of the array or None.</returns>
///
/// <remarks>
/// Time Complexity: O(1).
/// Space Complexity: O(1).
/// </remarks>
///
/// <example id="tryhead-1">
/// <code lang="fsharp">
/// let inputs = [| "banana"; "pear" |]
Expand Down Expand Up @@ -420,6 +482,11 @@ module Array =
///
/// <exception cref="T:System.ArgumentNullException">Thrown when the input array is null.</exception>
///
/// <remarks>
/// Time Complexity: O(n) where n is the length of the array.
/// Space Complexity: O(1).
/// </remarks>
///
/// <example id="trypick-1">
/// <code lang="fsharp">
/// let input = [| 1; 2; 3 |]
Expand Down Expand Up @@ -451,6 +518,11 @@ module Array =
/// <exception cref="T:System.ArgumentNullException">Thrown when the input array is null.</exception>
/// <exception cref="T:System.ArgumentException">Thrown when either targetIndex or count is negative.</exception>
///
/// <remarks>
/// Time Complexity: O(count) where count is the number of elements to fill.
/// Space Complexity: O(1).
/// </remarks>
///
/// <example id="fill-1">
/// <code lang="fsharp">
/// let target = [| 0; 1; 2; 3; 4; 5 |]
Expand All @@ -475,6 +547,11 @@ module Array =
///
/// <returns>The first result.</returns>
///
/// <remarks>
/// Time Complexity: O(n) where n is the length of the array.
/// Space Complexity: O(1).
/// </remarks>
///
/// <example id="pick-1">
/// <code lang="fsharp">
/// let input = [| 1; 2; 3 |]
Expand Down Expand Up @@ -507,6 +584,11 @@ module Array =
///
/// <exception cref="T:System.ArgumentNullException">Thrown when the input array is null.</exception>
///
/// <remarks>
/// Time Complexity: O(n) where n is the length of the array.
/// Space Complexity: O(k) where k is the number of elements for which the chooser returns Some.
/// </remarks>
///
/// <example id="choose-1">
/// <code lang="fsharp">
/// let input = [| Some 1; None; Some 2 |]
Expand Down Expand Up @@ -633,6 +715,11 @@ module Array =
/// <summary>Returns an empty array of the given type.</summary>
/// <returns>The empty array.</returns>
///
/// <remarks>
/// Time Complexity: O(1).
/// Space Complexity: O(1).
/// </remarks>
///
/// <example id="empty">
/// <code lang="fsharp">
/// Array.empty // Evaluates to [| |]
Expand Down Expand Up @@ -744,7 +831,10 @@ module Array =
///
/// <remarks>The predicate is applied to the elements of the input array. If any application
/// returns true then the overall result is true and no further elements are tested.
/// Otherwise, false is returned.</remarks>
/// Otherwise, false is returned.
/// Time Complexity: O(n) where n is the length of the array.
/// Space Complexity: O(1).
/// </remarks>
///
/// <param name="predicate">The function to test the input elements.</param>
/// <param name="array">The input array.</param>
Expand Down Expand Up @@ -822,6 +912,11 @@ module Array =
///
/// <exception cref="T:System.ArgumentNullException">Thrown when the input array is null.</exception>
///
/// <remarks>
/// Time Complexity: O(n) where n is the length of the array.
/// Space Complexity: O(k) where k is the number of elements that satisfy the predicate.
/// </remarks>
///
/// <example id="filter-1">
/// <code lang="fsharp">
/// let inputs = [| 1; 2; 3; 4 |]
Expand Down Expand Up @@ -1048,6 +1143,11 @@ module Array =
///
/// <exception cref="T:System.ArgumentNullException">Thrown when the input array is null.</exception>
///
/// <remarks>
/// Time Complexity: O(n) where n is the length of the array.
/// Space Complexity: O(1).
/// </remarks>
///
/// <example id="fold-1">
/// <code lang="fsharp">
/// type Charge =
Expand Down Expand Up @@ -1530,7 +1630,10 @@ module Array =
///
/// <returns>The length of the array.</returns>
///
/// <remarks>The notation <c>array.Length</c> is preferred.</remarks>
/// <remarks>The notation <c>array.Length</c> is preferred.
/// Time Complexity: O(1).
/// Space Complexity: O(1).
/// </remarks>
///
/// <exception cref="T:System.NullReferenceException">Thrown when the input array is null.</exception>
///
Expand Down Expand Up @@ -1580,6 +1683,11 @@ module Array =
///
/// <exception cref="T:System.ArgumentNullException">Thrown when the input array is null.</exception>
///
/// <remarks>
/// Time Complexity: O(n) where n is the length of the array.
/// Space Complexity: O(n) for the new array.
/// </remarks>
///
/// <example id="map-1">
/// <code lang="fsharp">
/// let inputs = [| "a"; "bbb"; "cc" |]
Expand Down Expand Up @@ -2268,7 +2376,10 @@ module Array =
/// <summary>Sorts the elements of an array, returning a new array. Elements are compared using <see cref="M:Microsoft.FSharp.Core.Operators.compare"/>. </summary>
///
/// <remarks>This is not a stable sort, i.e. the original order of equal elements is not necessarily preserved.
/// For a stable sort, consider using <see cref="M:Microsoft.FSharp.Collections.SeqModule.Sort"/>.</remarks>
/// For a stable sort, consider using <see cref="M:Microsoft.FSharp.Collections.SeqModule.Sort"/>.
/// Time Complexity: O(n log n) where n is the length of the array.
/// Space Complexity: O(n) for the new array.
/// </remarks>
///
/// <param name="array">The input array.</param>
///
Expand Down
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