How to detect Persian characters in string

Question

I've got a string value with a lot of different characters and I want to get a string contains with permitted characters.
For Example: I've got this string "geeks01$سهیلاطریقی03.02geeks!@!!." but I want to return this value:"0103.سهیلاطریقی02@."
The following Class is for detecting valid characters. and it works correctly .but I can't find an expressionfor persian characters.
Does anyone have any idea for fixing this problem? or any solution for better performance because I care about bottleneck and it must run about 8,000,000 times :)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {
        public static void Main()
        {
            string str = "geeks01$سهیلاطریقی03.02geeks!@!!.";
            splitString(str, true, false, true, new char[] { '@', '.' });
        }
        static string splitString(string str, bool keepNumber, bool keepEnglishAlpha, bool keepPersianbAlpha, char[] special)
        {
            StringBuilder value =
                     new StringBuilder();
            for (int i = 0; i < str.Length; i++)
            {
                if (Char.IsDigit(str[i]) && keepNumber == true)
                    value.Append(str[i]);

                if (keepEnglishAlpha == true)
                    if ((str[i] >= 'A' && str[i] <= 'Z') || (str[i] >= 'a' && str[i] <= 'z'))
                        value.Append(str[i]);

                if (keepPersianbAlpha == true)
                {
                    //todo
                }
                if (special.Length >= 1)
                {
                    foreach (var specialChar in special)
                    {
                        if (str[i] == specialChar)
                            value.Append(str[i]);
                    }
                }

            }
            return value.ToString();
        }
    }
}

Maybe this can help: https://stackoverflow.com/questions/10561590/regex-for-check-the-input-string-is-just-in-persian-language — i486, Jul 05 '20 at 10:59
This regex has error in `\s` @viveknuna **Error CS1009 Unrecognized escape sequence** — Soheila Tarighi, Jul 05 '20 at 11:05
@SoheilaTarighi try this `Regex.IsMatch(Text, @"^[\u0600-\u06ff\s]+$|[\u0750-\u077f\s]+$|[\ufb50-\ufc3f\s]+$|[\ufe70-\ufefc\s]+$|[\u06cc\s]+$|[\u067e\s]+$|[\u06af\s]$|[\u0691\s]+$|^$");` — Vivek Nuna, Jul 05 '20 at 11:06
Is this working as expected? Your `splitString` method invoking but you didn't set the result to any variable. I mean firstly, you have to set to `str` again then you can decide how to use it. `str = splitString(str,...` — gurkan, Jul 05 '20 at 11:35

score 3 · Accepted Answer · 2020-07-05T17:09:11.430

You can use the Enumerable.Aggregate method to improve the function and return the desired output based on the specified conditions.

using System;
using System.Linq;
using System.Globalization;
//...

//Suggested rename...
static string FilterString(
    string str, 
    bool keepNumber, 
    bool keepEnglishAlpha, 
    bool keepPersianbAlpha, 
    char[] special
    ) =>
    str.Aggregate(new StringBuilder(), (sb, c) =>
        (keepNumber && char.IsDigit(c))
        || (keepEnglishAlpha && ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')))
        || (keepPersianbAlpha && char.GetUnicodeCategory(c) == UnicodeCategory.OtherLetter)
        || (special != null && special.Contains(c))
        ? sb.Append(c) : sb.Append(string.Empty)).ToString();

Char.IsDigit method to recognize the digits.
Append the Latin characters if the keepEnglishAlpha is true.
Char.GetUnicodeCategory method which returns UnicodeCategory.OtherLetter for the Persian characters.
Append the special characters if the special array contains them.

Testing the mentioned above string:

public static void Main()
{
    var input = "geeks01$سهیلاطریقی03.02geeks!@!!.";
    var output = FilterString(input, true, false, true, new[] { '@', '.' });

    Console.WriteLine(output);
}

Writes:

01سهيلاطريقي03.02@.

Than you ,your solution works correctly, How I can replace ی ک arabic with ی ک persian ? @JQSOFT — Soheila Tarighi, Jul 05 '20 at 16:00
@SoheilaTarighi Most welcome Ma`am. Could you please give me a string with these characters to check it out? — , Jul 05 '20 at 16:14
For Example :`علي` Convert To `علی` and `شکاك` convert to `شکاک` how to detect arabic `ي ك` from input variable and convert to persian `ی ک` For Example : **"geeks01$سهيلاطريقي03.02geeks!@!!.";** and I want to return **01سهیلاطریقی03.02@.** remove arabic `ي` and replace with persian`ی` — Soheila Tarighi, Jul 05 '20 at 16:34
@SoheilaTarighi Use: `var s = "شکاك".Replace("\u0643", "\u06A9");` and `var s = "علي".Replace("\u064A", "\u0649");`. Check the links out for more: [Arabic Alphabet](https://en.wikipedia.org/wiki/Arabic_script_in_Unicode) and [Persian Alphabet](https://en.wikipedia.org/wiki/Persian_alphabet). — , Jul 05 '20 at 17:07

How to detect Persian characters in string

1 Answers1