EqualityComparer (TDesu.FSharp) | TDesu.FSharp

TDesu.FSharp

EqualityComparer Module

Namespace: TDesu.FSharp.Hashing
Assembly: TDesu.FSharp.dll

Factory for ad hoc IEqualityComparer{T} instances — for when a Dictionary{TKey,TValue}, HashSet{T}, or LINQ overload needs a custom key comparer but a full named type isn't worth declaring.

Functions and values

Function or value	Description
`EqualityComparer.create equals getHashCode` Full Usage: `EqualityComparer.create equals getHashCode` Parameters: equals : `'a -> 'a -> bool` - The equality function. getHashCode : `'a -> int` - The hash function. Returns: `IEqualityComparer<'a>`	Creates an IEqualityComparer{T} from an explicit equality function and hash function. equals : `'a -> 'a -> bool` The equality function. getHashCode : `'a -> int` The hash function. Returns: `IEqualityComparer<'a>` Example `let ordinalIgnoreCase = EqualityComparer.create (fun (a: string) b -> String.Equals(a, b, StringComparison.OrdinalIgnoreCase)) (fun s -> s.ToUpperInvariant().GetHashCode()) let set = HashSet<string>(ordinalIgnoreCase)` val ordinalIgnoreCase: obj Multiple items val string: value: 'T -> string -------------------- type string = System.String module String from Microsoft.FSharp.Core val set: obj
`EqualityComparer.createBy projection` Full Usage: `EqualityComparer.createBy projection` Parameters: projection : `'a -> 'b` - The function extracting the comparison key from an element. Returns: `IEqualityComparer<'a>`	Creates an IEqualityComparer{T} that compares and hashes elements by a projected key, using the key's own structural equality and hash code. projection : `'a -> 'b` The function extracting the comparison key from an element. Returns: `IEqualityComparer<'a>` Example `let byId = EqualityComparer.createBy (fun (p: Person) -> p.Id) let set = HashSet<Person>(byId)` val byId: obj val set: obj