C# 以第一个字符为例

我有一根绳子：大家好。我想从每个单词中提取前2个字符。结果是：Hetoal。我该怎么办？我试了试

字符串中的foreach字符串str

---

但是我收到了一个错误：无法将类型char转换为字符串

您需要将句子字符串拆分为单词，如下所示：

var sentence = "Hello to all.";
var words = sentence.Split(' ');

然后，您可以循环遍历句子中的每个单词，获取每个单词的前两个字符，并将它们附加到结果中，如下所示：

string result;
var resultBuilder = new StringBuilder();

foreach(string word in words)
{
    // Get the first two characters if word has two characters
    if (word.Length >= 2)
    {
        resultBuilder.Append(word.Substring(0, 2));
    }
    else
    {
        // Append the whole word, because there are not two first characters to get
        resultBuilder.Append(word);
    }
}

result = resultBuilder.ToString();

代码示例：

string someString = "Hello to all";
string[] words = someString.Split(' ');
string finalString = "";

foreach (string word in words) {
    finalString += word.Substring(0, 2);
}
// finalString = "Hetoal";

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这会将字符串拆分为单词，然后在每个单词前找到前2个字符，并将它们附加到最后一个字符串对象。

一种可能的解决方案是

string str = "Hello to all.";    
StringBuilder output = new StringBuilder();
foreach (string s in str.Split(' '))
{
   output.Append(s.Take(2));
}
string result = output.ToString();

你可以这样做

把你的绳子绕着空格分开

string[] words = s.Split(' ');
    foreach (string word in words)
    {
        Console.WriteLine(word.Substring(0,2));
    }

这里有一些linq：

string s = "Hello to all";
var words = s.Split(' ');
var result = new string(words.SelectMany(w=>w.Take(2)).ToArray());

---

您的错误是因为当您枚举一个字符串时，您得到的是每个字符的字符，而不是字符串。所以它应该是字符串中的foreachchar c。但这可能不是您想要的。这假设字符串中有2个字符。你可以用Math.Min2，word.Length来代替2。请解释一下你的答案的技术细节。这会导致He。甚至不按照writeString结果需要初始值的方式编译；

        String str = "Hello to all";
        String[] words = str.Split(' ');
        String completeWord = "";
        foreach (String word in words)
        {
            if(word.Length>1)
            completeWord+=word.Substring(0, 2);
        }

string str = "Hello to all";
string result = str.Split().Select(word => word.Substring(0, 2)).Aggregate((aggr, next) => aggr + next);

//original message  
string message = "hello to all";

//split into a string array using the space
var messageParts = message.Split(' ');

//The SelectMany here will select the first 2 characters of each
// array item. The String.Join will then concat them with an empty string ""
var result = String.Join("",messageParts.SelectMany(f=>f.Take(2)));

string word = "Hellow to all";   
string result = "";
foreach(var item in word.Take(2))
{
    result += item;
}

string myString = "Hello to all";
var result = myString
             .Split(' ')
             .Select(x => x.Substring(0,Math.Min(x.Length,2)))
             .Aggregate((y,z) => y + z);