有没有更好的方法来替换字符串?

我很惊讶Replace不接受字符数组或字符串数组。我想我可以写我自己的扩展,但我很好奇是否有更好的内置方式来做以下工作?注意最后一个Replace是一个字符串而不是字符。

myString.Replace(';', '\n').Replace(',', '\n').Replace('\r', '\n').Replace('\t', '\n').Replace(' ', '\n').Replace("\n\n", "\n");

当前回答

这是最短的方法:

myString = Regex.Replace(myString, @"[;,\t\r ]|[\n]{2}", "\n");

其他回答

就性能而言,这可能不是最好的解决方案,但它确实有效。

var str = "filename:with&bad$separators.txt";
char[] charArray = new char[] { '#', '%', '&', '{', '}', '\\', '<', '>', '*', '?', '/', ' ', '$', '!', '\'', '"', ':', '@' };
foreach (var singleChar in charArray)
{
   str = str.Replace(singleChar, '_');
}

你可以使用Linq的Aggregate函数:

string s = "the\nquick\tbrown\rdog,jumped;over the lazy fox.";
char[] chars = new char[] { ' ', ';', ',', '\r', '\t', '\n' };
string snew = chars.Aggregate(s, (c1, c2) => c1.Replace(c2, '\n'));

下面是扩展方法:

public static string ReplaceAll(this string seed, char[] chars, char replacementCharacter)
{
    return chars.Aggregate(seed, (str, cItem) => str.Replace(cItem, replacementCharacter));
}

扩展方法使用示例:

string snew = s.ReplaceAll(chars, '\n');

在构建了自己的解决方案并查看这里使用的解决方案后,我利用了一个不使用复杂代码且通常对大多数参数有效的答案。

Cover base cases where other methods are more appropriate. If there are no chars to replacement, return the original string. If there is only one, just use the Replace method. Use a StringBuilder and initialize the capacity to the length of the original string. After all, the new string being built will have the same length of the original string if its just chars being replaced. This ensure only 1 memory allocation is used for the new string. Assuming that the 'char' length could be small or large will impact performance. Large collections are better with hashsets, while smaller collections are not. This is a near-perfect use case for Hybrid Dictionaries. They switch to using a Hash based lookup once the collection gets too large. However, we don't care about the value of the dictionary, so I just set it to "true". Have different methods for StringBuilder verse just a string will prevent unnecessary memory allocation. If its just a string, don't instantiate a StringBuilder unless the base cases were checked. If its already a StringBuilder, then perform the replacements and return the StringBuilder itself (as other StringBuilder methods like Append do). I put the replacement char first, and the chars to check at the end. This way, I can leverage the params keyword for easily passing additional strings. However, you don't have to do this if you prefer the other order.

namespace Test.Extensions
{
    public static class StringExtensions
    {
        public static string ReplaceAll(this string str, char replacementCharacter, params char[] chars)
        {
            if (chars.Length == 0)
                return str;

            if (chars.Length == 1)
                return str.Replace(chars[0], replacementCharacter);

            StringBuilder sb = new StringBuilder(str.Length);

            var searcher = new HybridDictionary(chars.Length);
            for (int i = 0; i < chars.Length; i++)
                searcher[chars[i]] = true;

            foreach (var c in str)
            {
                if (searcher.Contains(c))
                    sb.Append(replacementCharacter);
                else
                    sb.Append(c);
            }

            return sb.ToString();
        }

        public static StringBuilder ReplaceAll(this StringBuilder sb, char replacementCharacter, params char[] chars)
        {
            if (chars.Length == 0)
                return sb;

            if (chars.Length == 1)
                return sb.Replace(chars[0], replacementCharacter);

            var searcher = new HybridDictionary(chars.Length);
            for (int i = 0; i < chars.Length; i++)
                searcher[chars[i]] = true;

            for (int i = 0; i < sb.Length; i++)
            {
                var val = sb[i];
                if (searcher.Contains(val))
                    sb[i] = replacementCharacter;
            }

            return sb;
        }
    }
}

使用正则表达式。替换,像这样:

  string input = "This is   text with   far  too   much   " + 
                 "whitespace.";
  string pattern = "[;,]";
  string replacement = "\n";
  Regex rgx = new Regex(pattern);
  string result = rgx.Replace(input, replacement);

这里是关于RegEx的MSDN文档的更多信息。取代

可以使用replace正则表达式。

s/[;,\t\r ]|[\n]{2}/\n/g

S /在开头表示搜索 [和]之间的字符是要搜索的字符(以任何顺序) 第二个/分隔搜索文本和替换文本

用英语来说,这是:

“寻找;或者,或者\t \r或者(空格)或者恰好两个连续的\n,然后把它替换成\n

在c#中,你可以做以下事情:(在导入system . text . regulareexpressions之后)

Regex pattern = new Regex("[;,\t\r ]|[\n]{2}");
pattern.Replace(myString, "\n");