如何将一组字符串分成C#中的组成字符？

Question

将字符串数组中的各个字符strArr分成这些字符数组的最佳方法是什么charArr,如下所示？

string[] strArr = { "123", "456", "789" };
char[] chrArr = { '1', '2', '3', '4', '5', '6', '7', '8', '9' };

这就是我目前正在做的事情,但我认为它不是很优雅:

int characterCount = 0;

for (int i = 0; i < strArr.Length; i++)
{
    characterCount += strArr[i].Length;
}

int indexCount = 0;
char[] chrArr = new char[characterCount];

for (int i = 0; i < strArr.Length; i++)
{
    for (int j = 0; j < strArr[i].Length; j++)
    {
        chrArr[indexCount] = strArr[i][j];
        indexCount++;
    }
}

Answer 1

那么,最简单的方法是:

char[] chrArr = string.Join(string.Empty, strArr).ToCharArray();

为了确保在这里没有混淆性能特征,这里有一个在LINQPad中测试的简短程序(不要忘记打开右下角的优化):

static string[] strArr = { "123", "456", "789" };

void Main()
{
    const int iterations = 10000000; // 10 million

    // Warm up JITter
    StringJoin();
    LINQSelectMany();
    LINQ();

    Stopwatch sw = Stopwatch.StartNew();
    for (int index = 0; index < iterations; index++)
        StringJoin();
    sw.Stop();
    sw.ElapsedMilliseconds.Dump("String.Join");

    sw.Restart();
    for (int index = 0; index < iterations; index++)
        LINQSelectMany();
    sw.Stop();
    sw.ElapsedMilliseconds.Dump("LINQ SelectMany");

    sw.Restart();
    for (int index = 0; index < iterations; index++)
        LINQ();
    sw.Stop();
    sw.ElapsedMilliseconds.Dump("LINQ");
}

public static void StringJoin()
{
    char[] c = string.Join(string.Empty, strArr).ToCharArray();
}

public static void LINQSelectMany()
{
    char[] c = strArr.SelectMany(s => s).ToArray();
}

public static void LINQ()
{
    var characters = (from s in strArr
                      from c in s
                      select c).ToArray();

}

如果您想使用它,可以在此处下载此LINQPad脚本.

输出(以毫秒为单位):

String.Join 
765 

LINQ SelectMany 
5098 

LINQ 
5465 

(关于性能测量代码的常见警告适用于此,指出我所犯的任何错误)

Answer 2

我会做:

char[] chrArr = strArr.SelectMany(s => s).ToArray();

Answer 3

var res = strArr.SelectMany(c => c.ToCharArray()).ToArray();