Error in string length - ios

Question

I have a table view which may contain number of data.
When user select one particular cell I set Id in string based on that selection. And then I am trying to find length of that string. But I am getting error in that. When I print that string it print its value.
Here is my code.
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
NSArray *charityArray = [dataArray objectAtIndex:indexPath.row];
charityId=[charityArray objectAtIndex:0];
NSLog(#"charityId%#",charityId);
NSLog(#"charitylen%d",[charityId length]);
}
and here is log screen.
2013-12-04 14:47:13.897 GratZeez[2178:a0b] charityId3
2013-12-04 14:47:13.897 GratZeez[2178:a0b] -[__NSCFNumber length]: unrecognized selector sent to instance 0xd174070 2013-12-04 14:47:13.899
GratZeez[2178:a0b] * Terminating app due to uncaught exception
'NSInvalidArgumentException', reason: '-[__NSCFNumber length]:
unrecognized selector sent to instance 0xd174070'
declaration of charityId:
#import <UIKit/UIKit.h>
#interface ExsitingCharityViewController : UIViewController<UITableViewDelegate,UITableViewDataSource,UITextFieldDelegate>
{
NSMutableArray *dataArray,*tempArray,*searchResultArray,*nameSearchArray;
BOOL search;
NSMutableDictionary *dataDict;
CGPoint originalCenter;
NSString *charityId;
}

Answer 1

try this code, Convert NSNumber to NSString and then use length
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
NSArray *charityArray = [dataArray objectAtIndex:indexPath.row];
charityId = [charityArray objectAtIndex:0];
NSString *charityString = [charityId stringValue];
NSLog(#"charityString = %#", charityString);
NSLog(#"charityString length = %d",[charityString length]);
}

Answer 2

As you post, charityId s not a NSNumber formatted type value.
If you want to know to length convert in to NSString formate,
Like, NSString* str = [NSString stringwithFormat:#"%#", charityId];
then you get length.

Answer 3

As the error log shows, you are sending the length message to a NSNumber object. According to your post, you seem to be trying to send it to a NSString but it is not a NSString.
-[__NSCFNumber length]: unrecognized selector sent to instance 0xd174070'

Answer 4

If you wish to use the %d string format specifier with an NSNumber you should convert the NSNumber object to an integer first:
NSLog(#"charityId%d",[charityId intValue]);

Answer 5

use this code for NSNumber to NSString
NSString *strId=[NSString StringWithFormat#"%d", charityId];
NSLog(#"charitylen%d",[strId length]);

Answer 6

If you are trying to NSLog an NSNumber do the following, replace this:
NSLog(#"charitylen%d",[charityId length]);
With this:
NSString *myString = [charityId stringValue];
NSLog(#"charitylen%#", myString);
And if you are trying to get the count of your Array use the following:
NSLog(#"charitylen%d",[charityId count]);
Update:
I have to opinions about your case:
1- It means that you are passing an NSNumber where the called code expects an NSString or some other object that has a length method. You can tell Xcode to break on exceptions so that you see where exactly the length method gets called.
2-I think it may because your charityId is empty or never used before you NSLog it .

Answer 7

-[__NSCFNumber length]: unrecognized selector sent to instance it's mean you are tried to get length of a number (i.e. int, NSInteger etc). so you need to typecast.
you can do it either using [NSString stringWithFormat:#"%d", charityId] or [charityId stringValue]
so just do below
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSArray *charityArray = [dataArray objectAtIndex:indexPath.row];
charityId=[charityArray objectAtIndex:0];
NSString *charityIdString=[NSString stringWithFormat:#"%d", charityId];
NSLog(#"charityId%#",charityIdString);
NSLog(#"charitylen%d",[charityIdString length]);
}