Say you got a string that's composed of one interesting data item per line, like/usr/share/dict/words
or from a script, and you want to process them. In this case turning a bunch of strings into floats:NSMutableArray *altitudes = [NSMutableArray array]; NSString *altitudeString = [self altitudeStringFromGoogle: coords]; [altitudeString enumerateLinesUsingBlock: ^(NSString *line, BOOL *stop) { float value = [line floatValue]; [altitudes addObject: [NSNumber numberWithFloat: value]]; }];