从字符串中删除特殊字符的最有效方法

我想从字符串中删除所有特殊字符。允许输入A-Z(大写或小写)、数字(0-9)、下划线(_)或点符号(.)。

我有以下，它是有效的，但我怀疑(我知道!)它不是很有效:

    public static string RemoveSpecialCharacters(string str)
    {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < str.Length; i++)
        {
            if ((str[i] >= '0' && str[i] <= '9')
                || (str[i] >= 'A' && str[i] <= 'z'
                    || (str[i] == '.' || str[i] == '_')))
                {
                    sb.Append(str[i]);
                }
        }

        return sb.ToString();
    }

最有效的方法是什么?正则表达式是什么样子的，它与普通字符串操作相比如何?

要清洗的字符串相当短，长度通常在10到30个字符之间。

当前回答

我将使用字符串替换为正则表达式搜索“特殊字符”，替换所有字符找到一个空字符串。

2009-07-13 15:38:48

其他回答

Use:

s.erase(std::remove_if(s.begin(), s.end(), my_predicate), s.end());

bool my_predicate(char c)
{
 return !(isalpha(c) || c=='_' || c==' '); // depending on you definition of special characters
}

你会得到一个干净的字符串s。

Erase()将去掉所有特殊字符，并且可以使用my_predicate()函数进行高度自定义。

2012-09-23 08:02:37

我将使用字符串替换为正则表达式搜索“特殊字符”，替换所有字符找到一个空字符串。

2009-07-13 15:38:48

我不确定这是最有效的方法，但对我来说很有效

 Public Function RemoverTildes(stIn As String) As String
    Dim stFormD As String = stIn.Normalize(NormalizationForm.FormD)
    Dim sb As New StringBuilder()

    For ich As Integer = 0 To stFormD.Length - 1
        Dim uc As UnicodeCategory = CharUnicodeInfo.GetUnicodeCategory(stFormD(ich))
        If uc <> UnicodeCategory.NonSpacingMark Then
            sb.Append(stFormD(ich))
        End If
    Next
    Return (sb.ToString().Normalize(NormalizationForm.FormC))
End Function

2015-08-25 00:16:48

简单的LINQ方法

string text = "123a22 ";
var newText = String.Join(string.Empty, text.Where(x => x != 'a'));

2021-09-11 09:15:37

I had to do something similar for work, but in my case I had to filter all that is not a letter, number or whitespace (but you could easily modify it to your needs). The filtering is done client-side in JavaScript, but for security reasons I am also doing the filtering server-side. Since I can expect most of the strings to be clean, I would like to avoid copying the string unless I really need to. This let my to the implementation below, which should perform better for both clean and dirty strings.

public static string EnsureOnlyLetterDigitOrWhiteSpace(string input)
{
    StringBuilder cleanedInput = null;
    for (var i = 0; i < input.Length; ++i)
    {
        var currentChar = input[i];
        var charIsValid = char.IsLetterOrDigit(currentChar) || char.IsWhiteSpace(currentChar);

        if (charIsValid)
        {
            if(cleanedInput != null)
                cleanedInput.Append(currentChar);
        }
        else
        {
            if (cleanedInput != null) continue;
            cleanedInput = new StringBuilder();
            if (i > 0)
                cleanedInput.Append(input.Substring(0, i));
        }
    }

    return cleanedInput == null ? input : cleanedInput.ToString();
}

2013-08-29 17:46:22

从字符串中删除特殊字符的最有效方法

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