ios - Convert spelled out number to number

Question

Is there a way, in Objective-C/Cocoa, to convert spelled out words to an NSNumber or equivalent in multiple languages?

For example:

convert three to 3 or convert ocho to 8 (Spanish).

Also slightly different, but 3 1/2 to 3.5

I could write my own code to do this, but I was hoping there was a built-in way to do this. Getting the translations of every number in several languages is something I'd like to avoid.

Answer 1

NSNumberFormatter can convert from text to numbers:

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

NSLog(@"%@", [formatter numberFromString:@"thirty-four"]);
NSLog(@"%@", [formatter numberFromString:@"three point five"]);

formatter.locale = [[NSLocale alloc]initWithLocaleIdentifier:[NSLocale localeIdentifierFromComponents:@{NSLocaleLanguageCode: @"es"}]];

NSLog(@"%@", [formatter numberFromString:@"ocho"]);

There are serious limitations as to what it can handle (it doesn't auto detect languages, if you deviate from the expected format (e.g. "thirty four" instead of "thirty-four"), fractions, etc.), but for the narrow domain, it appears to do the job.