Question

Goal: Group strings into into different letter groups.

Example letter groups: A to C, D to F, G to J, etc.

Pseudocode:

Loop through each group
Loop through each string in a collection
Print the string in the appropriate group

Question: What’s the best way to define a range of characters so we can use something like the following to check?

[NSCharacterSet(our custom character range) characterIsMember:[self.targetString.text characterAtIndex:0] ]

Answer 1

You can make your character sets as follows for arbitrary ranges of ASCII characters:

NSCharacterSet *a_to_d_Set = [NSCharacterSet characterSetWithRange:NSMakeRange('a', 'd'-'a' + 1)];
NSCharacterSet *e_to_l_Set = [NSCharacterSet characterSetWithRange:NSMakeRange('e', 'l'-'e' + 1)];

Of course, you could equivalently write:

NSCharacterSet *a_to_d_Set = [NSCharacterSet characterSetWithRange:NSMakeRange('a', 4)];