Question

environment: microsoft visual studio 2008 c#

How do I get the index of a whole word found in a string

string dateStringsToValidate = "birthdatecake||birthdate||other||strings";
string testValue = "birthdate";

var result = dateStringsToValidate.IndexOf(testValue);

It doesn’t have to be the way i did it either, for example, would it be better to use regular expressions or other methods?

Update:
The word is birthdate not birthdatecake. it doesn’t have to retrieve the match but the index should find the right word. i don’t think IndexOf is what i’m looking for then. Sorry for being unclear.

Answer 1

Use regular expressions for this

  string dateStringsToValidate = "birthdatecake||birthdate||other||strings";
  string testValue = "strings";
  var result = WholeWordIndexOf(dateStringsToValidate, testValue);

// ...

public int WholeWordIndexOf(string source, string word, bool ignoreCase = false)
{
  string testValue = "\\W?(" + word + ")\\W?";

  var regex = new Regex(testValue, ignoreCase ? 
         RegexOptions.IgnoreCase : 
         RegexOptions.None);

  var match = regex.Match(source);
  return match.Captures.Count == 0 ? -1 : match.Groups[0].Index;
}

Learn more about regex options in c# here

Another option, depending on your needs, is to split the string (as I see you have some delimiters). Please note the index returned by the this option is the index by word count, not character count (In this case, 1, as C# has zero based arrays).

  string dateStringsToValidate = "birthdatecake||birthdate||other||strings";
  var split = dateStringsToValidate.Split(new string[] { "||" }, StringSplitOptions.RemoveEmptyEntries);
  string testValue = "birthdate";
  var result = split.ToList().IndexOf(testValue);