Created
September 28, 2019 12:34
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Simple performance comparison between C# Dictionary and if / switch statements
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using System; | |
using System.Collections.Generic; | |
using System.Diagnostics; | |
namespace DictionaryTest | |
{ | |
class Program | |
{ | |
/* CPU: AMD Ryzen Threadripper 1950x @ 4.0 Ghz | |
* Count: 100000000 | |
* GetWeekDayNumberUsingIf, 400000000, 00:00:00.4316731 | |
* GetWeekDayNumberUsingSwitch, 400000000, 00:00:00.4087778 | |
* GetWeekDayNumberUsingDictionary, 400000000, 00:00:00.8983910 | |
*/ | |
/* https://dotnetfiddle.net/ | |
* Count: 100000000 | |
* GetWeekDayNumberUsingIf, 400000000, 00:00:01.9071346 | |
* GetWeekDayNumberUsingSwitch, 400000000, 00:00:00.9301885 | |
* GetWeekDayNumberUsingDictionary, 400000000, 00:00:02.7281431 | |
*/ | |
public static void Main(string[] args) | |
{ | |
int count = 100000000; | |
var methodsToTest = new List<KeyValuePair<string, Func<DayOfWeek, int>>>() | |
{ | |
new KeyValuePair<string, Func<DayOfWeek, int>>(nameof(GetWeekDayNumberUsingIf), GetWeekDayNumberUsingIf), | |
new KeyValuePair<string, Func<DayOfWeek, int>>(nameof(GetWeekDayNumberUsingSwitch), GetWeekDayNumberUsingSwitch), | |
new KeyValuePair<string, Func<DayOfWeek, int>>(nameof(GetWeekDayNumberUsingDictionary), GetWeekDayNumberUsingDictionary) | |
}; | |
foreach (var method in methodsToTest) | |
{ | |
int sum = 0; | |
Stopwatch stopwatch = new Stopwatch(); | |
stopwatch.Start(); | |
for (int i = 0; i < count; i++) | |
{ | |
DayOfWeek day = (DayOfWeek)(i % 7); | |
sum += method.Value(day); | |
} | |
stopwatch.Stop(); | |
Console.WriteLine($"{method.Key}, {sum}, {stopwatch.Elapsed}"); | |
} | |
} | |
static Dictionary<DayOfWeek, int> DayOfWeekNumbers = new Dictionary<DayOfWeek, int>() | |
{ | |
{ DayOfWeek.Monday, 1 }, | |
{ DayOfWeek.Tuesday, 2 }, | |
{ DayOfWeek.Wednesday, 3 }, | |
{ DayOfWeek.Thursday, 4 }, | |
{ DayOfWeek.Friday, 5}, | |
{ DayOfWeek.Saturday, 6 }, | |
{ DayOfWeek.Sunday, 7 } | |
}; | |
public static int GetWeekDayNumberUsingIf(DayOfWeek day) | |
{ | |
if (day == DayOfWeek.Monday) | |
{ | |
return 1; | |
} | |
else if (day == DayOfWeek.Tuesday) | |
{ | |
return 2; | |
} | |
else if (day == DayOfWeek.Wednesday) | |
{ | |
return 3; | |
} | |
else if (day == DayOfWeek.Thursday) | |
{ | |
return 4; | |
} | |
else if (day == DayOfWeek.Friday) | |
{ | |
return 5; | |
} | |
else if (day == DayOfWeek.Saturday) | |
{ | |
return 6; | |
} | |
else if (day == DayOfWeek.Sunday) | |
{ | |
return 7; | |
} | |
throw new ArgumentException(); | |
} | |
public static int GetWeekDayNumberUsingSwitch(DayOfWeek day) | |
{ | |
switch (day) | |
{ | |
case DayOfWeek.Monday: return 1; | |
case DayOfWeek.Tuesday: return 2; | |
case DayOfWeek.Wednesday: return 3; | |
case DayOfWeek.Thursday: return 4; | |
case DayOfWeek.Friday: return 5; | |
case DayOfWeek.Saturday: return 6; | |
case DayOfWeek.Sunday: return 7; | |
default: throw new ArgumentException(); | |
} | |
} | |
public static int GetWeekDayNumberUsingDictionary(DayOfWeek day) | |
{ | |
if (DayOfWeekNumbers.TryGetValue(day, out int value)) | |
{ | |
return value; | |
} | |
throw new ArgumentException(); | |
} | |
} | |
} |
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