Capitalizing words in a string using C#

Question

I need to take a string, and capitalize words in it. Certain words ("in", "at", etc.), are not capitalized and are changed to lower case if encountered. The first word should always be capitalized. Last names like "McFly" are not in the current scope, so the same rule will apply to them - only first letter capitalized.

For example: "of mice and men By CNN" should be changed to "Of Mice and Men by CNN". (Therefore ToTitleString won't work here.)

What would be the best way to do that?

I thought of splitting the string by spaces, and go over each word, changing it if necessary, and concatenating it to the previous word, and so on. It seems pretty naive and I was wondering if there's a better way to do it. I am using .NET 3.5.

Answer 1

Use

Thread.CurrentThread.CurrentCulture.TextInfo.ToTitleCase("of mice and men By CNN"); 

to convert to proper case and then you can loop through the keywords as you have mentioned.

Answer 2

Depending on how often you plan on doing the capitalization I'd go with the naive approach. You could possibly do it with a regular expression, but the fact that you don't want certain words capitalized makes that a little trickier.

You can do it with two passes using regular expressions:

var result = Regex.Replace("of mice and men isn't By CNN", @"\b(\w)", m => m.Value.ToUpper()); result = Regex.Replace(result, @"(\s(of|in|by|and)|\'[st])\b", m => m.Value.ToLower(), RegexOptions.IgnoreCase); 

This outputs Of Mice and Men Isn't by CNN.

The first expression capitalizes every letter on a word boundary and the second one downcases any words matching the list that are surrounded by white space.

The downsides to this approach is that you're using regexs (now you have two problems) and you'll need to keep that list of excluded words up to date. My regex-fu isn't good enough to be able to do it in one expression, but it might be possible.