Linq OrderBy but ignore first word if "the" - linq

Question

I have the following linq expression to do my ordering but was wondering how do I change this so that it will orderby name but ignore the first word if it is "the"
CaseStudies.OrderBy(a => a.Name)

Answer 1

Simplest way (if there is always lower-case the and no more than one space between words):
CaseStudies.OrderBy(a => a.Name.StartsWith("the ") ? a.Name.Substring(4) : a.Name)
You can create method with nice descriptive name and move this logic as well as null check and ignore case comparison there:
private string RemoveDefiniteArticle(string s)
{
if (String.IsNullOrEmpty(s))
return s;
if (s.StartsWith("the ", StringComparison.CurrentCultureIgnoreCase))
return s.Substring(4).TrimStart();
return s;
}
And use it
CaseStudies.OrderBy(a => RemoveDefiniteArticle(a.Name))

Answer 2

There are a surprising number of edge cases here. Suppose your list is
List<string> strings = new List<string> { "The aardvark", "the bear", "The cat", " dog", " elephant"};
Then the starting point is handling "the" at the start
strings.OrderBy(w => w.StartsWith("the ") ? w.Substring(4) : w);
Which gives:
elephant
dog
the bear
The cat
The aardvark
Ignoring case is better
strings.OrderBy(w => w.StartsWith("the ", StringComparison.CurrentCultureIgnoreCase) ? w.Substring(4) : w);
Giving:
elephant
The cat
dog
The aardvark
the bear
Handling multiple spaces after the leading "the" is even better, but not perfect:
strings.OrderBy(w => w.StartsWith("the ", StringComparison.CurrentCultureIgnoreCase) ? w.Substring(4).TrimStart() : w);
elephant
dog
The aardvark
the bear
The cat
Handling leading spaces before the leading "the" looks correct
strings.OrderBy(w => w.TrimStart().StartsWith("the ", StringComparison.CurrentCultureIgnoreCase) ? w.TrimStart().Substring(4).TrimStart() : w.TrimStart());
Gives:
The aardvark
the bear
The cat
dog
elephant
But there may be other edge cases around null/empty/whitespace checking at multiple points...

Answer 3

CaseStudies.OrderBy(a => a.Name.TrimStart().StartsWith("the ", StringComparison.CurrentCultureIgnoreCase) ? a.Name.TrimStart().Substring(4).TrimStart() : a.Name)