从C＃字符串中删除字符

时间：2011-09-14 04:58:19

标签： c# .net

如何从字符串中删除字符？例如："My name @is ,Wan.;'; Wan"。

我想从该字符串中删除字符'@', ',', '.', ';', '\''，使其变为"My name is Wan Wan"

24 个答案:

答案 0 :(得分：157)

var str = "My name @is ,Wan.;'; Wan";
var charsToRemove = new string[] { "@", ",", ".", ";", "'" };
foreach (var c in charsToRemove)
{
    str = str.Replace(c, string.Empty);
}

但如果你想删除所有非字母字符，我可能会建议另一种方法

var str = "My name @is ,Wan.;'; Wan";
str = new string((from c in str
                  where char.IsWhiteSpace(c) || char.IsLetterOrDigit(c)
                  select c
       ).ToArray());

答案 1 :(得分：56)

简单：

String.Join("", "My name @is ,Wan.;'; Wan".Split('@', ',' ,'.' ,';', '\''));

答案 2 :(得分：54)

听起来像RegEx的理想应用程序 - 一个专为快速文本操作而设计的引擎。在这种情况下：

Regex.Replace("He\"ll,o Wo'r.ld", "[@,\\.\";'\\\\]", string.Empty)

答案 3 :(得分：18)

对您的问题不太具体，可以通过白名单在正则表达式中列出可接受的字符，从字符串（空格除外）中删除所有标点符号：

string dirty = "My name @is ,Wan.;'; Wan";

// only space, capital A-Z, lowercase a-z, and digits 0-9 are allowed in the string
string clean = Regex.Replace(dirty, "[^A-Za-z0-9 ]", "");

请注意，在9之后有一个空格，以免从句子中删除空格。第三个参数是一个空字符串，用于替换不属于正则表达式的任何子字符串。

答案 4 :(得分：16)

 string x = "My name @is ,Wan.;'; Wan";
 string modifiedString = x.Replace("@", "").Replace(",", "").Replace(".", "").Replace(";", "").Replace("'", "");

答案 5 :(得分：9)

比较各种建议（以及在单字符替换与目标的各种大小和位置的情况下进行比较）。

在这种特殊情况下，拆分目标并加入替换（在这种情况下，空字符串）是最快的至少3倍。最终，性能根据替换的数量而有所不同，其中替换是在源中，以及源的大小。 #ymmv

结果

（完整结果here）

| Test                      | Compare | Elapsed                                                            |
|---------------------------|---------|--------------------------------------------------------------------|
| SplitJoin                 | 1.00x   | 29023 ticks elapsed (2.9023 ms) [in 10K reps, 0.00029023 ms per]   |
| Replace                   | 2.77x   | 80295 ticks elapsed (8.0295 ms) [in 10K reps, 0.00080295 ms per]   |
| RegexCompiled             | 5.27x   | 152869 ticks elapsed (15.2869 ms) [in 10K reps, 0.00152869 ms per] |
| LinqSplit                 | 5.43x   | 157580 ticks elapsed (15.758 ms) [in 10K reps, 0.0015758 ms per]   |
| Regex, Uncompiled         | 5.85x   | 169667 ticks elapsed (16.9667 ms) [in 10K reps, 0.00169667 ms per] |
| Regex                     | 6.81x   | 197551 ticks elapsed (19.7551 ms) [in 10K reps, 0.00197551 ms per] |
| RegexCompiled Insensitive | 7.33x   | 212789 ticks elapsed (21.2789 ms) [in 10K reps, 0.00212789 ms per] |
| Regex Insentive           | 7.52x   | 218164 ticks elapsed (21.8164 ms) [in 10K reps, 0.00218164 ms per] |

测试线束（LinqPad）

（注意：Perf和Vs为timing extensions I wrote） 

void test(string title, string sample, string target, string replacement) {
    var targets = target.ToCharArray();

    var tox = "[" + target + "]";
    var x = new Regex(tox);
    var xc = new Regex(tox, RegexOptions.Compiled);
    var xci = new Regex(tox, RegexOptions.Compiled | RegexOptions.IgnoreCase);

    // no, don't dump the results
    var p = new Perf/*<string>*/();
        p.Add(string.Join(" ", title, "Replace"), n => targets.Aggregate(sample, (res, curr) => res.Replace(new string(curr, 1), replacement)));
        p.Add(string.Join(" ", title, "SplitJoin"), n => String.Join(replacement, sample.Split(targets)));
        p.Add(string.Join(" ", title, "LinqSplit"), n => String.Concat(sample.Select(c => targets.Contains(c) ? replacement : new string(c, 1))));
        p.Add(string.Join(" ", title, "Regex"), n => Regex.Replace(sample, tox, replacement));
        p.Add(string.Join(" ", title, "Regex Insentive"), n => Regex.Replace(sample, tox, replacement, RegexOptions.IgnoreCase));
        p.Add(string.Join(" ", title, "Regex, Uncompiled"), n => x.Replace(sample, replacement));
        p.Add(string.Join(" ", title, "RegexCompiled"), n => xc.Replace(sample, replacement));
        p.Add(string.Join(" ", title, "RegexCompiled Insensitive"), n => xci.Replace(sample, replacement));

    var trunc = 40;
    var header = sample.Length > trunc ? sample.Substring(0, trunc) + "..." : sample;

    p.Vs(header);
}

void Main()
{
    // also see https://stackoverflow.com/questions/7411438/remove-characters-from-c-sharp-string

    "Control".Perf(n => { var s = "*"; });


    var text = "My name @is ,Wan.;'; Wan";
    var clean = new[] { '@', ',', '.', ';', '\'' };

    test("stackoverflow", text, string.Concat(clean), string.Empty);


    var target = "o";
    var f = "x";
    var replacement = "1";

    var fillers = new Dictionary<string, string> {
        { "short", new String(f[0], 10) },
        { "med", new String(f[0], 300) },
        { "long", new String(f[0], 1000) },
        { "huge", new String(f[0], 10000) }
    };

    var formats = new Dictionary<string, string> {
        { "start", "{0}{1}{1}" },
        { "middle", "{1}{0}{1}" },
        { "end", "{1}{1}{0}" }
    };

    foreach(var filler in fillers)
    foreach(var format in formats) {
        var title = string.Join("-", filler.Key, format.Key);
        var sample = string.Format(format.Value, target, filler.Value);

        test(title, sample, target, replacement);
    }
}

答案 6 :(得分：7)

最简单的方法是使用String.Replace：

String s = string.Replace("StringToReplace", "NewString");

答案 7 :(得分：6)

另一个简单的解决方案：

var forbiddenChars = @"@,.;'".ToCharArray();
var dirty = "My name @is ,Wan.;'; Wan";
var clean = new string(dirty.Where(c => !forbiddenChars.Contains(c)).ToArray());

答案 8 :(得分：5)

new List<string> { "@", ",", ".", ";", "'" }.ForEach(m => str = str.Replace(m, ""));

答案 9 :(得分：4)

字符串只是一个字符数组，所以使用Linq进行替换（类似于上面的Albin，除了使用linq contains语句进行替换）：

var resultString = new string(
        (from ch in "My name @is ,Wan.;'; Wan"
         where ! @"@,.;\'".Contains(ch)
         select ch).ToArray());

第一个字符串是替换chars in和的字符串 second是包含字符的简单字符串

答案 10 :(得分：2)

似乎最简单的方法是组合LINQ和string.Concat：

var input = @"My name @is ,Wan.;'; Wan";
var chrs = new[] {'@', ',', '.', ';', '\''};
var result = string.Concat(input.Where(c => !chrs.Contains(c)));
// => result = "My name is Wan Wan"

请参阅C# demo。请注意，string.Concat是string.Join("", ...)的快捷方式。

请注意，使用正则表达式删除单个已知字符仍然可以动态构建，尽管相信正则表达式较慢。但是，这里有一种构建这样一个动态正则表达式的方法（你需要的只是一个字符类）：

var pattern = $"[{Regex.Escape(new string(chrs))}]+";
var result = Regex.Replace(input, pattern, string.Empty);

见another C# demo。正则表达式看起来像[@,\.;']+（匹配一个或多个（+）连续出现的@，,，.，;或{ {1}}字符）其中点不必转义，但必须使用'来转义必须转义的其他字符，例如Regex.Escape，\，{{1或者^，它在你无法预测的角色类中的位置。

答案 11 :(得分：2)

根据@drzaus的性能数据，这是使用最快算法的扩展方法。

public static class StringEx
{
    public static string RemoveCharacters(this string s, params char[] unwantedCharacters) 
        => s == null ? null : string.Join(string.Empty, s.Split(unwantedCharacters));
}

用法

var name = "edward woodward!";
var removeDs = name.RemoveCharacters('d', '!');
Assert.Equal("ewar woowar", removeDs); // old joke

答案 12 :(得分：2)

这里有很多好的答案，这里是我的补充以及可用于帮助测试正确性的几个单元测试，我的解决方案类似于上面的@Rianne，但使用ISet为替换字符提供O（1）查找时间（也类似于@Albin Sunnanbo的Linq解决方案）。

    using System;
    using System.Collections.Generic;
    using System.Linq;

    /// <summary>
    /// Returns a string with the specified characters removed.
    /// </summary>
    /// <param name="source">The string to filter.</param>
    /// <param name="removeCharacters">The characters to remove.</param>
    /// <returns>A new <see cref="System.String"/> with the specified characters removed.</returns>
    public static string Remove(this string source, IEnumerable<char> removeCharacters)
    {
        if (source == null)
        {
            throw new  ArgumentNullException("source");
        }

        if (removeCharacters == null)
        {
            throw new ArgumentNullException("removeCharacters");
        }

        // First see if we were given a collection that supports ISet
        ISet<char> replaceChars = removeCharacters as ISet<char>;

        if (replaceChars == null)
        {
            replaceChars = new HashSet<char>(removeCharacters);
        }

        IEnumerable<char> filtered = source.Where(currentChar => !replaceChars.Contains(currentChar));

        return new string(filtered.ToArray());
    }

NUnit（2.6+）测试

using System;
using System.Collections;
using System.Collections.Generic;
using NUnit.Framework;

[TestFixture]
public class StringExtensionMethodsTests
{
    [TestCaseSource(typeof(StringExtensionMethodsTests_Remove_Tests))]
    public void Remove(string targetString, IEnumerable<char> removeCharacters, string expected)
    {
        string actual = StringExtensionMethods.Remove(targetString, removeCharacters);

        Assert.That(actual, Is.EqualTo(expected));
    }

    [TestCaseSource(typeof(StringExtensionMethodsTests_Remove_ParameterValidation_Tests))]
    public void Remove_ParameterValidation(string targetString, IEnumerable<char> removeCharacters)
    {
        Assert.Throws<ArgumentNullException>(() => StringExtensionMethods.Remove(targetString, removeCharacters));
    }
}

internal class StringExtensionMethodsTests_Remove_Tests : IEnumerable
{
    public IEnumerator GetEnumerator()
    {
        yield return new TestCaseData("My name @is ,Wan.;'; Wan", new char[] { '@', ',', '.', ';', '\'' }, "My name is Wan Wan").SetName("StringUsingCharArray");
        yield return new TestCaseData("My name @is ,Wan.;'; Wan", new HashSet<char> { '@', ',', '.', ';', '\'' }, "My name is Wan Wan").SetName("StringUsingISetCollection");
        yield return new TestCaseData(string.Empty, new char[1], string.Empty).SetName("EmptyStringNoReplacementCharactersYieldsEmptyString");
        yield return new TestCaseData(string.Empty, new char[] { 'A', 'B', 'C' }, string.Empty).SetName("EmptyStringReplacementCharsYieldsEmptyString");
        yield return new TestCaseData("No replacement characters", new char[1], "No replacement characters").SetName("StringNoReplacementCharactersYieldsString");
        yield return new TestCaseData("No characters will be replaced", new char[] { 'Z' }, "No characters will be replaced").SetName("StringNonExistantReplacementCharactersYieldsString");
        yield return new TestCaseData("AaBbCc", new char[] { 'a', 'C' }, "ABbc").SetName("CaseSensitivityReplacements");
        yield return new TestCaseData("ABC", new char[] { 'A', 'B', 'C' }, string.Empty).SetName("AllCharactersRemoved");
        yield return new TestCaseData("AABBBBBBCC", new char[] { 'A', 'B', 'C' }, string.Empty).SetName("AllCharactersRemovedMultiple");
        yield return new TestCaseData("Test That They Didn't Attempt To Use .Except() which returns distinct characters", new char[] { '(', ')' }, "Test That They Didn't Attempt To Use .Except which returns distinct characters").SetName("ValidateTheStringIsNotJustDistinctCharacters");
    }
}

internal class StringExtensionMethodsTests_Remove_ParameterValidation_Tests : IEnumerable
{
    public IEnumerator GetEnumerator()
    {
        yield return new TestCaseData(null, null);
        yield return new TestCaseData("valid string", null);
        yield return new TestCaseData(null, new char[1]);
    }
}

答案 13 :(得分：2)

我不妨把它扔出去。

进行扩展以从字符串中删除字符：

public static string RemoveChars(this string input, params char[] chars)
{
    var sb = new StringBuilder();
    for (int i = 0; i < input.Length; i++)
    {
        if (!chars.Contains(input[i]))
            sb.Append(input[i]);
    }
    return sb.ToString();
}

它可以这样使用：

string str = "My name @is ,Wan.;'; Wan";
string cleanedUpString = str.RemoveChars('@', ',', '.', ';', '\'');

或者就像这样：

string str = "My name @is ,Wan.;'; Wan".RemoveChars('@', ',', '.', ';', '\'');

答案 14 :(得分：1)

旧学校复制/踩踏：

  private static string RemoveDirtyCharsFromString(string in_string)
     {
        int index = 0;
        int removed = 0;

        byte[] in_array = Encoding.UTF8.GetBytes(in_string);

        foreach (byte element in in_array)
        {
           if ((element == ' ') ||
               (element == '-') ||
               (element == ':'))
           {
              removed++;
           }
           else
           {
              in_array[index] = element;
              index++;
           }
        }

        Array.Resize<byte>(ref in_array, (in_array.Length - removed));
        return(System.Text.Encoding.UTF8.GetString(in_array, 0, in_array.Length));
     }

不确定效率w.r.t.其他方法（即在C＃执行中作为副作用发生的所有函数调用和实例化的开销）。

答案 15 :(得分：1)

我使用扩展方法和字符串数组，我认为string[]比char[]更有用，因为char也可以是字符串：

public static class Helper
{
    public static string RemoverStrs(this string str, string[] removeStrs)
    {
        foreach (var removeStr in removeStrs)
            str = str.Replace(removeStr, "");
        return str;
    }
}

然后你可以在任何地方使用它：

string myname = "My name @is ,Wan.;'; Wan";
string result = myname.RemoveStrs(new[]{ "@", ",", ".", ";", "\\"});

答案 16 :(得分：1)

我需要从XML文件中删除特殊字符。这是我的方法。 char.ToString（）是这段代码中的英雄。

string item = "<item type="line" />"
char DC4 = (char)0x14;
string fixed = item.Replace(DC4.ToString(), string.Empty);

答案 17 :(得分：1)

new[] { ',', '.', ';', '\'', '@' }
.Aggregate("My name @is ,Wan.;'; Wan", (s, c) => s.Replace(c.ToString(), string.Empty));

答案 18 :(得分：0)

这是我写的一种方法，该方法略有不同。我没有指定要删除的字符，而是告诉我的方法我要保留的字符-它将删除所有其他字符。

在OP的示例中，他只想保留字母字符和空格。这是调用我的方法的样子（C# demo）：

var str = "My name @is ,Wan.;'; Wan";

// "My name is Wan Wan"
var result = RemoveExcept(str, alphas: true, spaces: true);

这是我的方法：

/// <summary>
/// Returns a copy of the original string containing only the set of whitelisted characters.
/// </summary>
/// <param name="value">The string that will be copied and scrubbed.</param>
/// <param name="alphas">If true, all alphabetical characters (a-zA-Z) will be preserved; otherwise, they will be removed.</param>
/// <param name="numerics">If true, all alphabetical characters (a-zA-Z) will be preserved; otherwise, they will be removed.</param>
/// <param name="dashes">If true, all alphabetical characters (a-zA-Z) will be preserved; otherwise, they will be removed.</param>
/// <param name="underlines">If true, all alphabetical characters (a-zA-Z) will be preserved; otherwise, they will be removed.</param>
/// <param name="spaces">If true, all alphabetical characters (a-zA-Z) will be preserved; otherwise, they will be removed.</param>
/// <param name="periods">If true, all decimal characters (".") will be preserved; otherwise, they will be removed.</param>
public static string RemoveExcept(string value, bool alphas = false, bool numerics = false, bool dashes = false, bool underlines = false, bool spaces = false, bool periods = false) {
    if (string.IsNullOrWhiteSpace(value)) return value;
    if (new[] { alphas, numerics, dashes, underlines, spaces, periods }.All(x => x == false)) return value;

    var whitelistChars = new HashSet<char>(string.Concat(
        alphas ? "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" : "",
        numerics ? "01234567890" : "",
        dashes ? "-" : "",
        underlines ? "_" : "",
        periods ? "." : "",
        spaces ? " " : ""
    ).ToCharArray());

    var scrubbedValue = value.Aggregate(new StringBuilder(), (sb, @char) => {
        if (whitelistChars.Contains(@char)) sb.Append(@char);
        return sb;
    }).ToString();

    return scrubbedValue;
}

答案 19 :(得分：0)

在相同情况下通常使用的一种强大的方法：

private string Normalize(string text)
{
        return string.Join("",
            from ch in text
            where char.IsLetterOrDigit(ch) || char.IsWhiteSpace(ch)
            select ch);
}

享受...

答案 20 :(得分：0)

这是删除文件名中无效字符的好方法：

string.Join(string.Empty, filename.Split(System.IO.Path.GetInvalidFileNameChars()));

答案 21 :(得分：0)

您可以删除非字符。 使用 array 和 string[] non_character = (new string[] {"@", ",", ".", ";", "'"}); string text = "My name @is ,Wan.;'; Wan"; string final_str = ""; foreach (string str in non_character) { final_str = text.replace(str, ""); } Console.WriteLine(final_str); 。

示例：

不能使用单引号，因为这是一个字符串。

class HelloCodiva {
    public static void main(String[] args) {
        System.out.println("Formatted: "
            + bold("bold") + " " + italic("italic") + " " + bold(italic("both")));
    }

    static CharSequence bold(CharSequence cs) {
        return trans(cs, 0x1D400, 0x1D41A);
    }

    static CharSequence italic(CharSequence cs) {
        return trans(cs, 0x1D434, 0x1D44e);
    }

    static CharSequence trans(CharSequence cs, int upper, int lower) {
        return cs.codePoints()
            .map(cp -> cp >= 'A' && cp <= 'Z'? cp + upper - 'A':
                       cp >= 'a' && cp <= 'z'? cp + lower - 'a':
                       cp >= 0x1D400 && cp <= 0x1D433? cp + 104:
                       cp >= 0x1D434 && cp <= 0x1D467? cp + 52:
                       cp)
            .collect(StringBuilder::new,
                     StringBuilder::appendCodePoint, StringBuilder::append);
    }
}

这很简单...

答案 22 :(得分：0)

如果要删除所有空格和特殊字符

        var input = Console.ReadLine();
        foreach (var item in input)
        {
            var limit = ((int)item);

            if (limit>=65 && limit<=90 || limit>=97 && limit<= 122)
            {
                Console.Write(item);
            }
            
        }

答案 23 :(得分：-2)

如果要替换'['']'，可以尝试以下操作：

foreach(var c in "[ \"]")
{
    string s = c + "";
    inputText = inputText.Replace(s, "");
}
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