Checking multiple contains on one string

Question

So I have a conditional that currently looks like this...

if (input.Contains(",") || input.Contains("/") || input.Contains(@"\") || input.Contains("."))

I need to add a few more characters that I want to check for and was wondering if there's a more condensed syntax to accomplish the same thing? Something similar to SQL's IN operator?

if ( input IN (",", "/", @"\", ....etc )  )

Anybody know of any cool tricks to accomplish this without adding lots of code?

Auspice

similar to this question #195430 – Lamere

I saw that question, I was hoping I could find a easier solution since I know all the characters I'm searching for ahead of time (which I have thanks for all the answers!). – Auspice

possible duplicate of VB.NET - Adding more than 1 string to .contains – Maracaibo

Answer 1

Consider using Regex (specify characters you want to check in brackets - remember that some of them must be escaped):

Regex.IsMatch(input, @"[,/]");

or

new[] {",", "/"}.Any(input.Contains)

Altricial

Answer 2

How about this?

    if(input.IndexOfAny(new char[] { ',', '/', '\\', '.' })>=0)
    {

    }

Eslinger

Just one thing: IndexOfAny handles only single characters, it doesn't handle strings. – Altricial

In the OP only single characters are checked for. – Eslinger

of course, that was just a side note, because IndexOf actually has an overloaded version with string. – Altricial

@Altricial nope msdn.microsoft.com/en-us/library/… – Erotomania

Answer 3

Does this win for shortest?

@".,/\".Any(input.Contains)

Touchhole

Answer 4

"asdfasdf".ContainsAny(".","/","4");

public static bool ContainsAny(this string stringToCheck, params string[] parameters)
{
    return parameters.Any(parameter => stringToCheck.Contains(parameter));
}

Charlena

Doesn't work in C#. The type string does not contain a definition for "ContainsAny" – Homeomorphism

I think, he is asking you to create your own method ContainsAny(arg1, arg2). He showed that as well. – Gentianaceous

Answer 5

Try

If (input.IndexOfAny(new char[] { ',', '/', '\\', '.' }) >= 0) {
    ...
}

or

If (input.IndexOfAny(@",/\.".ToCharArray()) >= 0) {
    ...
}

Viscometer

Answer 6

You could use some Linq:

if ( ",/\\.".ToCharArray().Any( c => input.Contains( c ) ) )

Bowne

Answer 7

You could use String.IndexOfAny -- it will scan the string for any one of a set of characters in an array:

if (e.Label.IndexOfAny(new char[]{',', '/', @'\', '.' /* other chars here */}) > -1)

Materiel

Answer 8

An extension method could make things look clean. Have a look at the following.

 public static bool ContainsChar(this string input, params char[] characters)
        {
            foreach (var character in characters)
            {
                if (input.Contains(character))
                {
                    return true;
                }
            }
            return false;
        }

The method's parameters are variadic, so you can add as many chars as you want separated by commas. If you're not comfortable using extension methods, modify to the following:

public static bool ContainsChar(string input, params char[] characters)
            {
                foreach (var character in characters)
                {
                    if (input.Contains(character))
                    {
                        return true;
                    }
                }
                return false;
            }

Example usage follows:

string myString = "this is my string";
//extension
if (myString.ContainsChar('.', '*', '%')) //do something

//static method
if (ContainsChar(myString, '.', '*', '%')) //do something

Optimal