Parallel.For、Parallel.Foreach 的使用

 

以下為演示 Parallel.For 與 Parallel.ForEach 的用法

//產生測試資料
List<string> testData = new List<string>();
//產生10組亂數字串
for (int i = 0; i < 10; i++)
{
    testData.Add(RndChars(20));
}
foreach (var item in testData)
{
    Console.WriteLine(item);
}
Console.WriteLine();



//for語法
List<string> resultData = new List<string>();
//找出 testData 中包含a 或 包含 abc的字串
for (int i = 0; i < testData.Count(); i++)
{
    if (testData[i].Contains(“a”) || testData[i].Contains(“abc”))
    {
        resultData.Add(testData[i]);
    }
}
foreach (var item in resultData)
{
    Console.WriteLine(item);
}
Console.WriteLine();
//Parallel.For語法
List<string> resultData2 = new List<string>();
Parallel.For(0, testData.Count() - 1, (i, loopState) =>
{
    string data = testData[i];
    if (data.Contains(“a”) || data.Contains(“abc”))
    {
        resultData2.Add(data);
    }
});
foreach (var item in resultData)
{
    Console.WriteLine(item);
}
Console.WriteLine();
//Parallel.ForEach語法
List<string> resultData3 = new List<string>();
Parallel.ForEach(testData, (item, loopState) =>
{
    //string data = testData[i];
    if (item.Contains(“a”) || item.Contains(“abc”))
    {
        resultData3.Add(item);
    }
});
foreach (var item in resultData)
{
    Console.WriteLine(item);
}
Console.WriteLine();
//亂數產生n字元的字串
string RndChars(int n)
{
    var characters = “ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789”;
    char[] chars = new char[n];
    for (int i = 0; i < n; i++)
    {
        chars[i] = characters[new Random().Next(characters.Length)];
    }
    return new string(chars);
}