c# Regex- Remove string which developed only combination of special charter

问题

I am looking for regular expression by which I can ignore strings which is only combination of All special charters.

Example

List<string> liststr = new List<string>() { "a b", "c%d", " ", "% % % %" ,"''","&","''","'"}; etc...

I need result of this one

{ "a b", "c%d"}

回答1:

Use this one :

.*[A-Za-z0-9].*

It matches at least one alphanumeric character. Doing this, it will take any string that is not only symbols/special chars. It does the output you want, see here : demo

回答2:

You can use this, too, to match string without any Unicode letter:

var liststr = new List<string>() { "a b", "c%d", " ", "% % % %", "''", "&", "''", "'" };
var rx2 = @"^\P{L}+$";
var res2 = liststr.Where(p => !Regex.IsMatch(p, rx2)).ToList();

Output:

I also suggest creating the regex object as a private static readonly field, with Compiled option, so that performance is not impacted.

private static readonly Regex rx2 = new Regex(@"^\P{L}+", RegexOptions.Compiled);
... (and inside the caller)
var res2 = liststr.Where(p => !rx2.IsMatch(p)).ToList();

回答3:

You can use a very simple regex like

Regex regex = new Regex(@"^[% &']+$");

Where

• [% &'] Is the list of special characters that you wish to include

Example

List<string> liststr = new List<string>() { "a b", "c%d", " ", "% % % %" ,"''","&","''","'"};
List<string> final = new List<string>();

Regex regex = new Regex(@"^[% &']+$");

foreach ( string str in liststr)
{
        if (! regex.IsMatch(str))
            final.Add(str);
}

Will give an output as

final = {"a b", "c%d"}

来源：https://stackoverflow.com/questions/29790137/c-sharp-regex-remove-string-which-developed-only-combination-of-special-charter