[C#] Array Conversion 성능 비교

1. 개요

Array 간의 데이터 타입 변환을 수행하고 성능을 비교한다.

 

2. 비교할 구현 코드

• For loop
• Linq Select
• Array.ConvertAll

[Test]
public void TestConvertPerf()
{
    PerfBenchmark bench = new PerfBenchmark("Convert Benchmark");
    var intArr = RandomUtils.GenerateInt(500000);
    int repSize = 1000;
    bench.Start();
    for (int i = 0; i < repSize; i++)
    {
        ToDoubleArray(intArr);
        bench.SaveCheckpoint();
    }
    bench.Stop();
    Console.WriteLine($"Avg, Std of for Loop: {bench.CalculateAverage()}, {bench.CalculateStandardDeviation()}");

    bench.ClearCheckpoint();
    bench.Start();
    for (int i = 0; i < repSize; i++)
    {
        ToDoubleArray2(intArr);
        bench.SaveCheckpoint();
    }
    bench.Stop();
    Console.WriteLine($"Avg, Std of Linq Select: {bench.CalculateAverage()}, {bench.CalculateStandardDeviation()}");

    bench.ClearCheckpoint();
    bench.Start();
    for (int i = 0; i < repSize; i++)
    {
        ToDoubleArray3(intArr);
        bench.SaveCheckpoint();
    }
    bench.Stop();
    Console.WriteLine($"Avg, Std of Array.ConvertAll: {bench.CalculateAverage()}, {bench.CalculateStandardDeviation()}");
}

public static double[] ToDoubleArray(int[] array)
{
    double[] doubleArray = new double[array.Length];
    for (int i = 0; i < array.Length; i++)
    {
        doubleArray[i] = array[i];
    }
    return doubleArray;
}

public static double[] ToDoubleArray2(int[] array)
{
    return array.Select(arr => (double)arr).ToArray();
}

public static double[] ToDoubleArray3(this int[] array)
{
    return Array.ConvertAll(array, (ii) => (double)ii);
}

 

3. 벤치 테스트 결과

성능상에 Array.ConvertAll이 For loop보다 근소하게 빠르며, Linq 의 함수는 역시 시간이 상당히 오래걸림.