将string字符串转换为array数组
NSArray *array = [str componentsSeparatedByString:@","];--分隔符
将array数组转换为string字符串
NSString *str = [array componentsJoinedByString:@","];--分隔符
将string字符串转换为array数组
NSArray *array = [str componentsSeparatedByString:@","];--分隔符
将array数组转换为string字符串
NSString *str = [array componentsJoinedByString:@","];--分隔符