Cast an NSDictionary value while applying an NSPredicate?

Posted by RickiG on Stack Overflow See other posts from Stack Overflow or by RickiG
Published on 2010-05-11T19:37:28Z Indexed on 2010/05/11 19:44 UTC
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Hi

I have an Array of NSDictionary objects. These Dictionaries are parsed from a JSON file. All value objects in the NSDictionary are of type NSString, one key is called "distanceInMeters".

I had planned on filtering these arrays using an NSPredicate, so I started out like this:

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(distanceInMeters <= %f)", newValue];
NSArray *newArray = [oldArray filteredArrayUsingPredicate:predicate];

I believe this would have worked if the value for the "distanceInMeters" key was an NSNumber, but because I have it from a JSON file everything is NSStrings. The above gives this error:* -[NSCFNumber length]: unrecognized selector sent to instance 0x3936f00**

Which makes sense as I had just tried to treat an NSString as an NSNumber.

Is there a way to cast the values from the dictionary while they are being filtered, or maybe a completely different way of getting around this?

Hope someone can help me :)

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