dotnet · BillWagner · Apr 12, 2022 · Apr 11, 2022
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+module equals1
+
+// <Snippet1>
+open System
+
+let temperatureInfos = 
+    [| Tuple.Create(2, 97.9, 97.8, 98.0, 98.2)
+       Tuple.Create(1, 98.6, 98.8, 98.8, 99.0)
+       Tuple.Create(2, 98.6, 98.6, 98.6, 98.4)
+       Tuple.Create(1, 98.4, 98.6, 99.0, 99.2)
+       Tuple.Create(2, 98.6, 98.6, 98.6, 98.4)
+       Tuple.Create(1, 98.6, 98.8, 98.8, 99.0) |]
+// Compare each item with every other item for equality.
+for ctr = 0 to temperatureInfos.Length - 1 do
+    let temperatureInfo = temperatureInfos[ctr]
+    for ctr2 = ctr + 1 to temperatureInfos.Length - 1 do
+        printfn $"{temperatureInfo} = {temperatureInfos[ctr2]}: {temperatureInfo.Equals temperatureInfos[ctr2]}"
+    printfn ""
+
+// The example displays the following output:
+//    (2, 97.9, 97.8, 98, 98.2) = (1, 98.6, 98.8, 98.8, 99): False
+//    (2, 97.9, 97.8, 98, 98.2) = (2, 98.6, 98.6, 98.6, 98.4): False
+//    (2, 97.9, 97.8, 98, 98.2) = (1, 98.4, 98.6, 99, 99.2): False
+//    (2, 97.9, 97.8, 98, 98.2) = (2, 98.6, 98.6, 98.6, 98.4): False
+//    (2, 97.9, 97.8, 98, 98.2) = (1, 98.6, 98.8, 98.8, 99): False
+//    
+//    (1, 98.6, 98.8, 98.8, 99) = (2, 98.6, 98.6, 98.6, 98.4): False
+//    (1, 98.6, 98.8, 98.8, 99) = (1, 98.4, 98.6, 99, 99.2): False
+//    (1, 98.6, 98.8, 98.8, 99) = (2, 98.6, 98.6, 98.6, 98.4): False
+//    (1, 98.6, 98.8, 98.8, 99) = (1, 98.6, 98.8, 98.8, 99): True
+//    
+//    (2, 98.6, 98.6, 98.6, 98.4) = (1, 98.4, 98.6, 99, 99.2): False
+//    (2, 98.6, 98.6, 98.6, 98.4) = (2, 98.6, 98.6, 98.6, 98.4): True
+//    (2, 98.6, 98.6, 98.6, 98.4) = (1, 98.6, 98.8, 98.8, 99): False
+//    
+//    (1, 98.4, 98.6, 99, 99.2) = (2, 98.6, 98.6, 98.6, 98.4): False
+//    (1, 98.4, 98.6, 99, 99.2) = (1, 98.6, 98.8, 98.8, 99): False
+//    
+//    (2, 98.6, 98.6, 98.6, 98.4) = (1, 98.6, 98.8, 98.8, 99): False
+// </Snippet1>
@@ -0,0 +1,40 @@
+module equals2
+
+// <Snippet2>
+open System
+open System.Collections
+
+type DoubleComparer<'T1, 'T2, 'T3, 'T4, 'T5 when 'T1: equality and 'T2: equality and 'T3: equality and 'T4: equality and 'T5: equality>(difference: double) =
+    let mutable argument = 0
+
+    interface IEqualityComparer with
+        member _.Equals(x, y) =
+            argument <- argument + 1
+
+            // Return true for Item1.
+            if argument = 1 then
+                true
+            else
+                let d1 = x :?> double
+                let d2 = y :?> double
+
+                d1 - d2 < d1 * difference
+
+        member _.GetHashCode(obj) =
+            match obj with
+            | :? 'T1 as obj -> obj.GetHashCode()
+            | :? 'T2 as obj -> obj.GetHashCode()
+            | :? 'T3 as obj -> obj.GetHashCode()
+            | :? 'T4 as obj -> obj.GetHashCode()
+            | _ -> (obj :?> 'T5).GetHashCode()   
+
+let getValues ctr =
+    // Generate four random numbers between 0 and 1
+    let rnd = Random(DateTime.Now.Ticks >>> 32 >>> ctr |> int)
+    Tuple.Create(ctr, rnd.NextDouble(), rnd.NextDouble(), rnd.NextDouble(), rnd.NextDouble())
+
+let value1 = getValues 1
+let value2 = getValues 2
+let iValue1 = value1
+printfn $"{value1} =\n{value2} :\n{(DoubleComparer<int, double, double, double, double> 0.01 :> IEqualityComparer).Equals(iValue1, value2)}"
+// </Snippet2>
@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="equals1.fs" />
+    <Compile Include="equals2.fs" />
+  </ItemGroup>
+</Project>
@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="item1.fs" />
+  </ItemGroup>
+</Project>
@@ -0,0 +1,22 @@
+module item1
+
+// <Snippet1>
+open System
+
+// Define array of tuples reflecting population change by state, 1990-2000.
+let statesData = 
+    [| Tuple.Create("California", 29760021, 33871648, 4111627, 13.8)
+       Tuple.Create("Illinois", 11430602, 12419293, 988691, 8.6)
+       Tuple.Create("Washington", 4866692, 5894121, 1027429, 21.1) |]
+
+// Display the items of each tuple
+printfn "%-12s%18s%18s%15s%12s\n" "State" "Population 1990" "Population 2000" "Change" "% Change"
+for stateData in statesData do
+    printfn $"{stateData.Item1,-12}{stateData.Item2,18:N0}{stateData.Item3,18:N0}{stateData.Item4,15:N0}{stateData.Item5,12:P1}"
+// The example displays the following output:
+//    State          Population 1990   Population 2000         Change    % Change
+//    
+//    California          29,760,021        33,871,648      4,111,627      13.8 %
+//    Illinois            11,430,602        12,419,293        988,691       8.6 %
+//    Washington           4,866,692         5,894,121      1,027,429      21.1 %
+// </Snippet1>
@@ -0,0 +1,52 @@
+// <Snippet1>
+open System
+
+let computeStatistics (players: Tuple<string, int, int, int, int>[]) = 
+    [| for player in players do
+        // Create result object containing player name and statistics.
+        Tuple.Create(player.Item1,  
+                     double player.Item3 / double player.Item2,
+                     double player.Item4 / double player.Item2,
+                     double player.Item4 / double player.Item3, 
+                     double player.Item5 / double player.Item3) |]
+
+
+// Organization of runningBacks 5-tuple:
+//    Component 1: Player name
+//    Component 2: Number of games played
+//    Component 3: Number of attempts (carries)
+//    Component 4: Number of yards gained 
+//    Component 5: Number of touchdowns   
+let runningBacks =
+    [| Tuple.Create("Payton, Walter", 190, 3838, 16726, 110)
+       Tuple.Create("Sanders, Barry", 153, 3062, 15269, 99)
+       Tuple.Create("Brown, Jim", 118, 2359, 12312, 106)
+       Tuple.Create("Dickerson, Eric", 144, 2996, 13259, 90)
+       Tuple.Create("Faulk, Marshall", 176, 2836, 12279, 100) |]
+// Calculate statistics.
+// Organization of runningStats 5-tuple:
+//    Component 1: Player name
+//    Component 2: Number of attempts per game
+//    Component 3: Number of yards per game
+//    Component 4: Number of yards per attempt 
+//    Component 5: Number of touchdowns per attempt   
+let runningStats = computeStatistics runningBacks
+
+// Display the result.          
+printfn "%-16s %5s %6s %7s %7s %7s %7s %5s %7s\n" "Name" "Games" "Att" "Att/Gm" "Yards" "Yds/Gm" "Yds/Att" "TD" "TD/Att"
+for i = 0 to runningBacks.Length - 1 do
+    printfn $"{runningBacks[i].Item1,-16} {runningBacks[i].Item2,5} {runningBacks[i].Item3,6:N0} {runningBacks[i].Item2,7:N1} {runningBacks[i].Item4,7:N0} {runningBacks[i].Item3,7:N1} {runningBacks[i].Item4,7:N2} {runningBacks[i].Item5,5} {runningBacks[i].Item5,7:N3}\n" 
+
+// The example displays the following output:
+//    Name             Games    Att  Att/Gm   Yards  Yds/Gm Yds/Att    TD  TD/Att
+//    
+//    Payton, Walter     190  3,838    20.2  16,726    88.0    4.36   110   0.029
+//    
+//    Sanders, Barry     153  3,062    20.0  15,269    99.8    4.99    99   0.032
+//    
+//    Brown, Jim         118  2,359    20.0  12,312   104.3    5.22   106   0.045
+//    
+//    Dickerson, Eric    144  2,996    20.8  13,259    92.1    4.43    90   0.030
+//    
+//    Faulk, Marshall    176  2,836    16.1  12,279    69.8    4.33   100   0.035
+// </Snippet1>
@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="example1.fs" />
+  </ItemGroup>
+</Project>
@@ -0,0 +1,46 @@
+module compareto1
+
+// <Snippet1>
+open System
+
+// Organization of runningBacks 5-tuple:
+//    Component 1: Player name
+//    Component 2: Number of games played
+//    Component 3: Number of attempts (carries)
+//    Component 4: Number of yards gained 
+//    Component 5: Number of touchdowns   
+let runningBacks =
+    [| Tuple.Create("Payton, Walter", 190, 3838, 16726, 110)
+       Tuple.Create("Sanders, Barry", 153, 3062, 15269, 99)
+       Tuple.Create("Brown, Jim", 118, 2359, 12312, 106)
+       Tuple.Create("Dickerson, Eric", 144, 2996, 13259, 90)
+       Tuple.Create("Faulk, Marshall", 176, 2836, 12279, 100) |]
+
+// Display the array in unsorted order.
+printfn "The values in unsorted order:"
+for runningBack in runningBacks do
+    printfn $"{runningBack}"
+printfn ""
+
+// Sort the array
+Array.Sort runningBacks
+
+// Display the array in sorted order.
+printfn "The values in sorted order:"
+for runningBack in runningBacks do
+    printfn $"{runningBack}"
+// The example displays the following output:
+//       The values in unsorted order:
+//       (Payton, Walter, 190, 3838, 16726, 110)
+//       (Sanders, Barry, 153, 3062, 15269, 99)
+//       (Brown, Jim, 118, 2359, 12312, 106)
+//       (Dickerson, Eric, 144, 2996, 13259, 90)
+//       (Faulk, Marshall, 176, 2836, 12279, 100)
+//       
+//       The values in sorted order:
+//       (Brown, Jim, 118, 2359, 12312, 106)
+//       (Dickerson, Eric, 144, 2996, 13259, 90)
+//       (Faulk, Marshall, 176, 2836, 12279, 100)
+//       (Payton, Walter, 190, 3838, 16726, 110)
+//       (Sanders, Barry, 153, 3062, 15269, 99)
+// </Snippet1>
@@ -0,0 +1,57 @@
+module compareto2
+
+// <Snippet2>
+open System
+open System.Collections
+open System.Collections.Generic
+
+type YardsGained<'T1, 'T2, 'T3, 'T4, 'T5>() =
+    interface IComparer with
+        member _.Compare(x, y) =
+            match x with
+            | :? Tuple<'T1, 'T2, 'T3, 'T4, 'T5> as tX ->
+                let tY = y :?> Tuple<'T1, 'T2, 'T3, 'T4, 'T5>
+                -1 * Comparer<'T4>.Default.Compare(tX.Item4, tY.Item4)             
+            | _ -> 0
+
+// Organization of runningBacks 5-tuple:
+//    Component 1: Player name
+//    Component 2: Number of games played
+//    Component 3: Number of attempts (carries)
+//    Component 4: Number of yards gained 
+//    Component 5: Number of touchdowns   
+let runningBacks =
+    [| Tuple.Create("Payton, Walter", 190, 3838, 16726, 110)
+       Tuple.Create("Sanders, Barry", 153, 3062, 15269, 99)
+       Tuple.Create("Brown, Jim", 118, 2359, 12312, 106)
+       Tuple.Create("Dickerson, Eric", 144, 2996, 13259, 90)
+       Tuple.Create("Faulk, Marshall", 176, 2836, 12279, 100) |]
+
+// Display the array in unsorted order.
+printfn "The values in unsorted order:"
+for runningBack in runningBacks do
+    printfn $"{runningBack}"
+printfn ""
+
+// Sort the array
+Array.Sort(runningBacks, YardsGained<string, int, int, int, int>())
+
+// Display the array in sorted order.
+printfn "The values in sorted order:"
+for runningBack in runningBacks do
+    printfn $"{runningBack}"
+// The example displays the following output:
+//       The values in unsorted order:
+//       (Payton, Walter, 190, 3838, 16726, 110)
+//       (Sanders, Barry, 153, 3062, 15269, 99)
+//       (Brown, Jim, 118, 2359, 12312, 106)
+//       (Dickerson, Eric, 144, 2996, 13259, 90)
+//       (Faulk, Marshall, 176, 2836, 12279, 100)
+//       
+//       The values in sorted order:
+//       (Brown, Jim, 118, 2359, 12312, 106)
+//       (Dickerson, Eric, 144, 2996, 13259, 90)
+//       (Faulk, Marshall, 176, 2836, 12279, 100)
+//       (Payton, Walter, 190, 3838, 16726, 110)
+//       (Sanders, Barry, 153, 3062, 15269, 99)
+// </Snippet2>
@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="compareto2.fs" />
+    <Compile Include="compareto1.fs" />
+  </ItemGroup>
+</Project>
@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="tostring1.fs" />
+  </ItemGroup>
+</Project>
@@ -0,0 +1,16 @@
+// <Snippet1>
+open System
+
+// Define array of tuples reflecting population change by state, 1990-2000.
+let populationChanges = 
+    [| Tuple.Create("California", 29760021, 33871648, 4111627, 13.8) 
+       Tuple.Create("Illinois", 11430602, 12419293, 988691, 8.6)
+       Tuple.Create("Washington", 4866692, 5894121, 1027429, 21.1) |]
+// Display each tuple.
+for item in populationChanges do
+    printfn $"{item.ToString()}"
+// The example displays the following output:
+//       (California, 29760021, 33871648, 4111627, 13.8)
+//       (Illinois, 11430602, 12419293, 988691, 8.6)
+//       (Washington, 4866692, 5894121, 1027429, 21.1)
+// </Snippet1>