Seq.compareWith<'T> Function (F#)
Compares two sequences using the given comparison function, element by element.
Namespace/Module Path: Microsoft.FSharp.Collections.Seq
Assembly: FSharp.Core (in FSharp.Core.dll)
// Signature:
Seq.compareWith : ('T -> 'T -> int) -> seq<'T> -> seq<'T> -> int
// Usage:
Seq.compareWith comparer source1 source2
Parameters
comparer
Type: 'T -> 'T -> intA function that takes an element from each sequence and returns an int. If it evaluates to a non-zero value iteration is stopped and that value is returned.
source1
Type: seq<'T>The first input sequence.
source2
Type: seq<'T>The second input sequence.
Exceptions
Exception |
Condition |
|---|---|
Thrown when either of the input sequences is null. |
Return Value
Returns the first non-zero result from the comparison function. If the end of a sequence is reached it returns a -1 if the first sequence is shorter and a 1 if the second sequence is shorter.
Remarks
This function is named CompareWith in compiled assemblies. If you are accessing the function from a .NET language other than F#, or through reflection, use this name.
Example
The following example demonstrates the use of Seq.compareWith to compare two sequences using a custom comparison function.
let sequence1 = seq { 1 .. 10 }
let sequence2 = seq { 10 .. -1 .. 1 }
// Compare two sequences element by element.
let compareSequences = Seq.compareWith (fun elem1 elem2 ->
if elem1 > elem2 then 1
elif elem1 < elem2 then -1
else 0)
let compareResult1 = compareSequences sequence1 sequence2
match compareResult1 with
| 1 -> printfn "Sequence1 is greater than sequence2."
| -1 -> printfn "Sequence1 is less than sequence2."
| 0 -> printfn "Sequence1 is equal to sequence2."
| _ -> failwith("Invalid comparison result.")
Sequence1 is less than sequence2.
Platforms
Windows 8, Windows 7, Windows Server 2012, Windows Server 2008 R2
Version Information
F# Core Library Versions
Supported in: 2.0, 4.0, Portable