How do I split a string by a multi-character delimiter in C#?

http://msdn.microsoft.com/en-us/library/system.string.split.aspx

Example from the docs:

string source = "[stop]ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]";
string[] stringSeparators = new string[] {"[stop]"};
string[] result;

// ...
result = source.Split(stringSeparators, StringSplitOptions.None);

foreach (string s in result)
{
    Console.Write("'{0}' ", String.IsNullOrEmpty(s) ? "<>" : s);
}

You can use the Regex.Split method, something like this:

Regex regex = new Regex(@"\bis\b");
string[] substrings = regex.Split("This is a sentence");

foreach (string match in substrings)
{
   Console.WriteLine("'{0}'", match);
}

Edit: This satisfies the example you gave. Note that an ordinary String.Split will also split on the "is" at the end of the word "This", hence why I used the Regex method and included the word boundaries around the "is". Note, however, that if you just wrote this example in error, then String.Split will probably suffice.

string s = "This is a sentence.";
string[] res = s.Split(new string[]{ " is " }, StringSplitOptions.None);

for(int i=0; i<res.length; i++)
    Console.Write(res[i]);

EDIT: The "is" is padded on both sides with spaces in the array in order to preserve the fact that you only want the word "is" removed from the sentence and the word "this" to remain intact.

You can use String.Replace() to replace your desired split string with a character that does not occur in the string and then use String.Split on that character to split the resultant string for the same effect.

Here is an extension function to do the split with a string separator:

public static string[] Split(this string value, string seperator)
{
    return value.Split(new string[] { seperator }, StringSplitOptions.None);
}

Example of usage:

string mystring = "one[split on me]two[split on me]three[split on me]four";
var splitStrings = mystring.Split("[split on me]");