Question

这里是我要实现的示例：例如，给定字符串Something，如果要将所有出现的so替换为DDD，结果将是DDDmething。

这是我实施的方式；我的代码通过其特定位置找到了一个字符并对其进行了更改，但实际上我想实现上面所述的内容。

    static void Main(string[] args)
    {
        string str = "The Haunting of Hill House!";
        Console.WriteLine("String: " + str);

        // replacing character at position 7
        int pos = 7;
        char rep = 'p';

        string res = str.Substring(0, pos) + rep + str.Substring(pos + 1);
        Console.WriteLine("String after replacing a character: " + result);

        Console.ReadLine();
    }

Answer 1

这应该做您想要的。这个想法是使用IndexOf查找要替换的子字符串的索引，然后在替换之前附加子字符串，然后从找到的子字符串的末尾开始搜索。然后，在找到并替换所有子字符串之后，如果有的话，将原始字符串的其余部分追加到末尾。

请注意，这不会对输入进行任何检查，您确实应该使用string.Replace，因为我确信它的性能更高。

public string Replace(string input, string find, string replace)
{
    // The current index in the string where we are searching from
    int currIndex = 0;

    // The index of the next substring to replace
    int index = input.IndexOf(find);

    // A string builder used to build the new string
    var builder = new StringBuilder();

    // Continue until the substring is not found
    while(index != -1)
    {
        // If the current index is not equal to the substring location
        // when we need to append everything from the current position
        // to where we found the substring
        if(index != currIndex ) 
        {
            builder.Append(input.Substring(currIndex , index - currIndex));
        }

        // Now append the replacement
        builder.Append(replace);

        // Move the current position past the found substring
        currIndex = index + find.Length;

        // Search for the next substring.
        index = input.IndexOf(find, currIndex );
    }

    // If the current position is not the end of the string we need
    // to append the remainder of the string.
    if(currIndex < input.Length) 
    {
        builder.Append(input.Substring(currIndex));
    }

    return builder.ToString();
}

Answer 2

替代方法可能是用“ so”分割字符串，并用“ DDD”合并结果数组：

string result = string.Join("DDD", "something".Split(new[] { "so" }, StringSplitOptions.None));

Answer 3

您可以这样做：

var someString = "This is some sort of string.";

var resultIndex = 0;
var searchKey ="So";
var replacementString = "DDD";
while ((resultIndex = someString.IndexOf(searchKey, resultIndex, StringComparison.OrdinalIgnoreCase)) != -1)
{
  var prefix = someString.Substring(0, Math.Max(0, resultIndex - 1));
  var suffix = someString.Substring(resultIndex + searchKey.Length);
  someString = prefix + replacementString + suffix;
  resultIndex += searchKey.Length;
}

预期产生“这是字符串的DDDme DDDrt。” 。

给定一个字符串查找出现的位置并替换为另一个字符串而不使用string.replace（）

3 个答案: