C＃字符数组在特定索引处删除

Question

Not to sure the best way to remove the char from the char array if the char at a given index is a number.

private string TextBox_CharacterCheck(string tocheckTextBox)
{
    char[] charlist = tocheckTextBox.ToCharArray();
    foreach (char character in charlist)
    {
        if (char.IsNumber(character))
        {

        }

    }
    return (new string(charlist));
}

Thanks in advance.

// this is now resolved. thank you to all who contributed

Answer 1

您可以使用Linq的功能：

return new string(tocheckTextBox.Where(c => !char.IsNumber(c)).ToArray())

Answer 2

This is fairly easy using Regex:

var result = Regex.Replace("a1b2c3d4", @"\d", "");

(as @Adassko notes, you can use "[0-9]" instead of @"\\d" if you just want the digits 0 to 9, and not any other numeric characters).

You can also do it fairly efficiently using a StringBuilder:

var sb = new StringBuilder();
foreach (var ch in "a1b2c3d4")
{
    if (!char.IsNumber(ch))
    {
        sb.Append(ch);
    }   
}

var result = sb.ToString();

You can also do it with linq:

 var result = new string("a1b2c3d4".Where(x => !char.IsNumber(x)).ToArray());

Answer 3

Use Regex:

private string TextBox_CharacterCheck(string tocheckTextBox)
{
    return Regex.Replace(tocheckTextBox, @"[\d]", string.Empty);;
}

Answer 4

System.String is immutable. You could use string.Replace or a regular expression to remove unwanted characters into a new string.

Answer 5

your best bet is to use regular expressions. strings are immutable meaning that you can't change them - you need to rewrite the whole string - to do it in optimal way you should use StringBuilder class and Append every character that you want.

Also watch out for your code - char.IsNumber checks not only for characters 0 - 9 , it also returns true for every numeric character such as ٢ and you probably don't want that.

here's the full list of characters returning true :

0123456789٠١٢٣٤٥٦٧٨٩۰۱۲۳۴۵۶۷۸۹߀߁߂߃߄߅߆߇߈߉०१२३४५६७८९০১২৩৪৫৬৭৮৯੦੧੨੩੪੫੬੭੮੯૦૧૨૩૪૫૬૭૮૯୦୧୨୩୪୫୬୭୮୯௦௧௨௩௪௫௬௭௮௯౦౧౨౩౪౫౬౭౮౯೦೧೨೩೪೫೬೭೮೯൦൧൨൩൪൫൬൭൮൯๐๑๒๓๔๕๖๗๘๙໐໑໒໓໔໕໖໗໘໙༠༡༢༣༤༥༦༧༨༩၀၁၂၃၄၅၆၇၈၉႐႑႒႓႔႕႖႗႘႙០១២៣៤៥៦៧៨៩᠐᠑᠒᠓᠔᠕᠖᠗᠘᠙᥆᥇᥈᥉᥊᥋᥌᥍᥎᥏᧐᧑᧒᧓᧔᧕᧖᧗᧘᧙᭐᭑᭒᭓᭔᭕᭖᭗᭘᭙᮰᮱᮲᮳᮴᮵᮶᮷᮸᮹᱀᱁᱂᱃᱄᱅᱆᱇᱈᱉᱐᱑᱒᱓᱔᱕᱖᱗᱘᱙꘠꘡꘢꘣꘤꘥꘦꘧꘨꘩꣐꣑꣒꣓꣔꣕꣖꣗꣘꣙꤀꤁꤂꤃꤄꤅꤆꤇꤈꤉꩐꩑꩒꩓꩔꩕꩖꩗꩘꩙０１２３４５６７８９

you should also use [0-9] rather than \\d in your regular expressions if you want only parsable digits.

You can also use a trick to .Split your string on your character, then .Join it back. This not only allows you to remove one or more characters, it also lets you to replace it with some other character. I use this trick to remove incorrect characters from file name:

string.Join("-", possiblyIncorrectFileName.Split(Path.GetInvalidFileNameChars()))

this code will replace any character that cannot be used in valid file name to -

Answer 6

You can use LINQ to remove the char from the char array if the char at a given index is a number.

CODE

//This will return you the list of char discarding the number.
var removedDigits = tocheckTextBox.Where(x => !char.IsDigit(x)); 

//This will return the string without numbers.
string output = string.join("", removedDigits);