Question

Possible Duplicate:
How to convert an NSString into an NSNumber

How can I convert an NSString (@”Five” for example) into an NSNumber (5). I have looked to see if any questions answer this on Stack Overflow, but it seems that many people have been asking for a number to string conversion – not the other way around.

Answer 1

This works roughly and should at least get you started:

NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
formatter.numberStyle = NSNumberFormatterSpellOutStyle;

NSArray *testStrings = @[@"Five",@"twenty-four",@"Nineteen",@"One hundred forty-two"];

for (NSString *test in testStrings) {

    NSNumber *result = [formatter numberFromString:[test lowercaseString]];

    NSLog (@"String %@ -> %@ as number",test,result);

}

Some things to think about:

• You’ll want to set the locale correctly to either some fixed locale (if these strings are all coming from a server or something in one constant language) or let it float to the user’s locale (if the user is the one entering the strings)
• As others have pointed out, this parser may not be sophisticated enough for your needs. For example, the last string “thirty three” actually returns the wrong result. The others work correctly. As @JonathanGrynspan suggested, if you tell us more about your goal here, someone can maybe suggest something better.

I hope that helps.