在C＃

Question

有一个面试问题，要求我用C＃中的下一个单词附上单词的每个最后一个字母。例如，输入是＆＃34;嘿，你好世界＆＃34;输出应该是＆＃34;他yhell oworld＆＃34;。

我已经提出了下面的代码，但有更好的方法吗？也许在LINQ？

string inputString = "Hey Hello World";
string[] stringArray = inputString.Split(' ').ToArray();
StringBuilder resultString = new StringBuilder("");
StringBuilder lastLetter = new StringBuilder(""); 

for (int i = 0; i < stringArray.Length; i++)
{
    string temp = stringArray[i].ToString();

    if (i < stringArray.Length - 2)
    {
        resultString.Append(lastLetter + temp.Substring(0, temp.Length - 1));
        lastLetter.Clear();
        lastLetter.Append(" " + temp.Substring(temp.Length - 1, 1));
    }
    else
        resultString.Append(lastLetter + temp.Substring(0, temp.Length));
}

Console.WriteLine(resultString);

Answer 1

如何使用正则表达式

var newtext = Regex.Replace("Hey hello world", @"(.) "," $1");

Answer 2

您不必要地使代码复杂化。只需用以前的字符替换空格。

        var input = "Hey Hello world";
        var arr = input.Trim().ToCharArray();
        for(int i =0; i< arr.Length; i++)
        {
            if(arr[i]==' ')
            {
                var temp = arr[i];
                arr[i] = arr[i - 1];
                arr[i - 1] = temp;
            }
        }
        Console.WriteLine(arr);

Answer 3

这是一个LINQ解决方案，因为这似乎是OP正在寻找的东西。

using System;
using System.Linq;

public class Program
{
    const char space = ' ';

    public static string DoHomework(string input)
    {
        return new string
        (
            input.Select( (c,i) => 
            {
                if (i == 0 || i == input.Length-1) return c;
                if (c == space) return input[i-1];
                if (input[i+1] == space) return space;
                return c;
            }).ToArray()    
        );
    }

    public static void Main()
    {
        var input = "Hey hello world";
        var output = DoHomework(input);

        Console.WriteLine(output);
    }
}

输出：

He yhell oworld

在DotNetFiddle

上试用

Answer 4

创建一个空字符串。这将是输出。 然后循环遍历原始字符串，并根据下一个字符将字符附加到输出字符串。

static void Main()
        {
            string inputString = "Hey Hello World";

            string sout = "";//the empty string

            int i = 0;//indexer available outside of the for loop
            for (; i < inputString.Length - 2; ++i)
                if (inputString[i + 1] == ' ')//next character is space
                {
                    sout += ' ';
                    sout += inputString[i];
                    ++i;//because we forwarded 2 places
                }
                else
                {
                    sout += inputString[i];
                }


            sout += inputString[i];//the leftover

            if (i + 1 < inputString.Length)
                sout += inputString[i + 1];//if the last word was only 1 character long than we append it too

            Console.WriteLine(sout);
            Console.ReadKey();
        }