New Strings Chapter

[rbwhitaker]

I'm planning on chopping up Level 7 into two levels, one focused on Console and one focused on strings.

I've been feeling for a while that strings deserve a deeper analysis, and this would become the place for that.

The one major reservation I have about this is that the book has not really dealt with instance methods until later. And this would demand it come front and center in this new strings chapter. But I think that's probably okay. By this point in the book, you're probably ready for it, and this gives you a set of string power tools that will serve you well through the rest of the book. (For example, people are constantly mentioning ToLower() in Discord. And... it is only mentioned as a side effect in the section about extension methods.)

So here's a list of things that I'd likely include. First, from the existing content:

• Escape sequences
• String interpolation, including alignment and formatting.

New C# 11 features:

• Triple-quoted strings.
• Maybe UTF8 strings, but I'm not sure I'm going to spend much time on them in this book, and given the complexities of ReadOnlySpan<byte>, I may save this for later, even if I do cover it.

String instance methods and properties:

• First, a discussion on instance methods in the first place.
• Also, probably a brief discussion on immutability, but maybe not using that word. Just the idea that strings don't change once made. You just create new strings based on it.
• Compare? I don't know about this one. It makes more sense in an ordering context.
• Contains
• StartsWith and EndsWith
• Format, but probably only as a side note about string interpolation
• foreach to get each character? (Hm... maybe not, because this is probably before loops. But then maybe that deserves to be visited in the foreach chapter.
• IndexOf and LastIndexOf
• Insert
• String interning?
• IsNullOrEmpty and IsNullOrWhiteSpace?
• Join? This pretty much completely uses arrays, so maybe this waits?
• PadLeft and PadRight
• Remove
• Replace
• ReplaceLineEndings? This just seems... less useful.
• Split. This is covered later in the book in the file stuff. Moving it forward could actually open up some other interesting possibilities.
• Substring
• ToUpper and ToLower
• ToUpperInvariant and ToLowerInvariant?
• Equals
• Trim, TrimEnd, TrimStart

There's also an open question here: should this be a text chapter, rather than a strings chapter? Should I include char stuff?

If I included char stuff, I think the main thing I'd point out is all of the IsAscii, IsDigit, IsLetter, IsNumber stuff. This is mentioned later in the book, but it is done as a random hint in a challenge.

[rbwhitaker]

This chapter now exists, and was put in after arrays, so that it can leverage some of the array features. I've left the string formatting in the console chapter, because I think it is too convenient to wait on, and is most useful in a display situation anyway.