Learning the iOS 4 SDK for JavaScript Programmers

About NSString

The NSString class provides a more convenient way of working with strings than dealing with traditional C strings. That’s not to say that you are completely free and clear of C strings (NSStrings are stored as C strings beneath the covers), but for day-to-day string handling, you will likely stay within the NSString realm.

One more potential complexity is character encoding, especially if your app retrieves explicitly encoded text from a server. The NSString class has many methods that convert and accommodate a wide range of character encodings. If these issues are important to your coding, you should read the “String Programming Guide for Cocoa” in the SDK documentation once you have a good working knowledge of the basics revealed in this chapter.

Regular expression support is available only beginning with iOS 4. Chapter 9 demonstrates how to use regular expressions with NSString objects. If your app is designed to include earlier iOS versions and you want to use regular expressions, you’ll be out of luck (although some third-party libraries exist).

As is the case with all basic data classes in Cocoa Touch, once you create an object, you usually cannot modify its content. That is to say, you cannot insert or delete segments of the string. All NSString methods that sound on the surface to be modifying the current object (e.g., the uppercaseString method) actually perform the modifications and return a new NSString object. You can, of course, assign the new object to ...