[C#] Improving my ToProper() Function

[wey97]

Can you code it better?

public string ToProper(string src)
{
	string[] s = src.Split(new char[] { ' ' });
	string retval = String.Empty;
	int n = 0;

	foreach (string str in s)
	{
		if (str == String.Empty)
		{
			retval += " ";
		}
		else
		{
			retval += (str[0].ToString().ToUpper() +
				str.Substring(1, str.Length - 1).ToLower() +
				(n < s.Length - 1 ? " " : ""));
		}

		n++;
	}

	return retval;
}

[wild_bill]

This is a little shorter

using System.Text.RegularExpressions;
		public string ToPropper(string src)
		{
				src = " " + src;
				foreach (Match mt in Regex.Matches(src," [a-z]"))
				{
					src = src.Replace(mt.Value,mt.Value.ToUpper());
				}
			
			return src.TrimStart();
		}

[wey97]

This is a little shorter

using System.Text.RegularExpressions;
		public string ToPropper(string src)
		{
				src = " " + src;
				foreach (Match mt in Regex.Matches(src," [a-z]"))
				{
					src = src.Replace(mt.Value,mt.Value.ToUpper());
				}
			
			return src.TrimStart();
		}

I like the idea of using regular expressions, but I think you misunderstood what I was trying to do with the function. A ToProper() Function should analyze all letters in a string, capitalize the first letter of each word, and convert additional trailing letters to lower case. It should also ignore all spaces and non alpha characters.

For example, with this input:

ToProper(@"THiS IS aN iMprOPEr Case STRING")

the function should return:

"This Is An Improper Case String"

[wild_bill]

Easy enough fix:

		public string ToPropper(string src)
		{
				src = " " + src.ToLower();
				foreach (Match mt in Regex.Matches(src," [a-z]"))
				{
					//replace first letter of each word with uppercase
					src = src.Replace(mt.Value,mt.Value.ToUpper());
				}
			
			return src.TrimStart();
		}

[wey97]

Easy enough fix:

		public string ToPropper(string src)
		{
				src = " " + src.ToLower();
				foreach (Match mt in Regex.Matches(src," [a-z]"))
				{
					//replace first letter of each word with uppercase
					src = src.Replace(mt.Value,mt.Value.ToUpper());
				}
			
			return src.TrimStart();
		}

Your code works if you only have spaces before a letter but what about tabs, and new lines?

Also it would seem to be inefficient. This code eliminates the scan to convert to all lower case.

The regular expression "\w" matches words:

public string ToProper(string src)
{

	// match one or more words
	foreach (Match mt in Regex.Matches(src, @"\w+"))
	{
		src = src.Replace(mt.Value, mt.Value.Substring(0, 1).ToUpper() +
			mt.Value.Substring(1, mt.Value.Length - 1).ToLower());
	}

	return src;
}

Pass the function this string and you'll see a problem:
ToProper("THIS \nwOrD haS \ta hyPhen: half-baked")

The newline, tab, and spaces are all OK but when the 'a' by itself is found, it replaces all other lowercase 'a's with 'A' so the result is:

"This \nWord HAs \tA Hyphen: HAlf-BAked"

and another problem is evident: 'half' and 'baked' was recognized as two separate words even though it's one hyphenated word.

This leads to the following:

public string ToProper(string src)
{
	string skip = " \t\n";

	// match zero or one whitespace followed by one or more words
	// followed by zero or one hyphen followed by zero or one tic followed 
	// by zero or more words followed by zero or more whitespaces

	foreach (Match mt in Regex.Matches(src, @"\s?\w+-?'?\w*\s*"))
	{
		 //if the first character is a white space character		 
		if (skip.IndexOf(mt.Value[0]) >= 0)
		{
		    src = src.Replace(mt.Value, mt.Value.Substring(0, 2).ToUpper() +
		    mt.Value.Substring(2, mt.Value.Length - 2).ToLower());
		}
		else
		{
		    src = src.Replace(mt.Value, mt.Value.Substring(0, 1).ToUpper() +
		        mt.Value.Substring(1, mt.Value.Length - 1).ToLower());
		}
	}

	return src;
}

{EDIT}
Didn't realize there was a Char.IsWhiteSpace(char) Function:

public string ToProper(String src)
{
	// match zero or one whitespace followed by one or more words
	// followed by zero or one - followed by zero or one ' followed 
	// by zero or more words followed by zero or more whitespaces

	foreach (Match mt in Regex.Matches(src, @"\s?\w+-?'?\w*\s*"))
	{
		 //if the first character is a white space character
		if(Char.IsWhiteSpace(mt.Value[0]))
		{
			src = src.Replace(mt.Value, mt.Value.Substring(0, 2).ToUpper() +
				mt.Value.Substring(2, mt.Value.Length - 2).ToLower());
		}
		else
		{
			src = src.Replace(mt.Value, mt.Value.Substring(0, 1).ToUpper() +
				mt.Value.Substring(1, mt.Value.Length - 1).ToLower());
		}
	}

	return src;
}

Now see if you can code this better.

[wild_bill]

How about this?

		public string ToPropper(string src)
		{
				//need to append character at the end of the string, as the
				//regex pattern will remove the last word
				src = src + " a";
				//create buffer to store new text
				System.Text.StringBuilder sb = new System.Text.StringBuilder();
				//Groups
				foreach (Match mt in Regex.Matches(src,"(\\b\\w)(.*?)(?=\\b\\w)",RegexOptions.Singleline))
				{
					//replace first letter of each match with uppercase
					sb.Append(mt.Groups[1].Value.ToUpper());
					//replace everything else with lowercase
					sb.Append(mt.Groups[2].Value.ToLower());
				}
					
			return sb.ToString();
		}

[wey97]

How about this?

That doesn't work for the string I posted above.

[wild_bill]

Try it again, I changed the search expression.