How do I get a list of all the printable characters in C#?

Question

I'd like to be able to get a char array of all the printable characters in C#, does anybody know how to do this?

edit:

By printable I mean the visible European characters, so yes, umlauts, tildes, accents etc.

Answer 1

This will give you a list with all characters that are not considered control characters:

List<Char> printableChars = new List<char>();
for (int i = char.MinValue; i <= char.MaxValue; i++)
{
    char c = Convert.ToChar(i);
    if (!char.IsControl(c))
    {
        printableChars.Add(c);
    }
}

You may want to investigate the other Char.IsXxxx methods to find a combination that suits your requirements.

Answer 2

Here's a LINQ version of Fredrik's solution. Note that Enumerable.Range yields an IEnumerable<int> so you have to convert to chars first. Cast<char> would have worked in 3.5SP0 I believe, but as of 3.5SP1 you have to do a "proper" conversion:

var chars = Enumerable.Range(0, char.MaxValue+1)
                      .Select(i => (char) i)
                      .Where(c => !char.IsControl(c))
                      .ToArray();

I've created the result as an array as that's what the question asked for - it's not necessarily the best idea though. It depends on the use case.

Note that this also doesn't consider full Unicode characters, only those in the basic multilingual plane. I don't know what it returns for high/low surrogates, but it's worth at least knowing that a single char doesn't really let you represent everything :(

Answer 3

A LINQ solution (based on Fredrik Mörk's):

Enumerable.Range(char.MinValue, char.MaxValue).Select(c => (char)c).Where(
    c => !char.IsControl(c)).ToArray();

Answer 4

TLDR Answer

Use this Regex...

var regex = new Regex(@"[^\p{Cc}^\p{Cn}^\p{Cs}]");

TLDR Explanation

• ^\p{Cc} : Do not match control characters.
• ^\p{Cn} : Do not match unassigned characters.
• ^\p{Cs} : Do not match UTF-8-invalid characters.

Working Demo

I test two strings in this demo: "Hello, World!" and "Hello, World!" + (char)4. char(4) is the character for END TRANSMISSION.

using System;
using System.Text.RegularExpressions;

public class Test {
    public static MatchCollection getPrintableChars(string haystack) {
        var regex = new Regex(@"[^\p{Cc}^\p{Cn}^\p{Cs}]");
        var matches = regex.Matches(haystack);
        return matches;
    }
    public static void Main() {
        var teststring1 = "Hello, World!";
        var teststring2 = "Hello, World!" + (char)4;
        
        var teststring1unprintablechars = getPrintableChars(teststring1);
        var teststring2unprintablechars = getPrintableChars(teststring2);
        
        Console.WriteLine("Testing a Printable String: " + teststring1unprintablechars.Count + " Printable Chars Detected");
        Console.WriteLine("Testing a String With 1-Unprintable Char: " + teststring2unprintablechars.Count + " Printable Chars Detected");
        
        foreach (Match unprintablechar in teststring1unprintablechars) {
            Console.WriteLine("String 1 Printable Char:" + unprintablechar);
        }
        
        foreach (Match unprintablechar in teststring2unprintablechars) {
            Console.WriteLine("String 2 Printable Char:" + unprintablechar);
        }
    }
}

Full Working Demo at IDEOne.com

Alternatives

• \P{C} : Match only visible characters. Do not match any invisible characters.
• \P{Cc} : Match only non-control characters. Do not match any control characters.
• \P{Cc}\P{Cn} : Match only non-control characters that have been assigned. Do not match any control or unassigned characters.
• \P{Cc}\P{Cn}\P{Cs} : Match only non-control characters that have been assigned and are UTF-8 valid. Do not match any control, unassigned, or UTF-8-invalid characters.
• \P{Cc}\P{Cn}\P{Cs}\P{Cf} : Match only non-control, non-formatting characters that have been assigned and are UTF-8 valid. Do not match any control, unassigned, formatting, or UTF-8-invalid characters.

Source and Explanation

Take a look at the Unicode Character Properties available that can be used to test within a regex. You should be able to use these regexes in Microsoft .NET, JavaScript, Python, Java, PHP, Ruby, Perl, Golang, and even Adobe. Knowing Unicode character classes is very transferable knowledge, so I recommend using it!