[__NSCFString count]: Unrecognized selector

Question

I know this has been asked before, but there is no answer that I have found useful.

First off here is my code

// load the .csv file with all information about the track

            NSError *error;
            NSString *filepath = [[NSBundle mainBundle] pathForResource:@"file" ofType:@"csv" inDirectory:nil];

            NSString *datastring1 = [NSString stringWithContentsOfFile:filepath encoding:NSUTF8StringEncoding error:&error];
            NSArray *datarow = [datastring1 componentsSeparatedByString:@"\r"];

            //fill arrays with the values from .csv file
            NSArray *data_seg = [datarow objectAtIndex:0]; //segment number
            NSArray *data_slength = [datarow objectAtIndex:1]; //strait length
            NSArray *data_slope = [datarow objectAtIndex:2]; //slope
            NSArray *data_cradius = [datarow objectAtIndex:3]; //circle radius
            NSArray *data_cangle = [datarow objectAtIndex:4]; //circle angle

            NSLog(@"%i", [data_seg count]);

Okay, so there is the code, and I read that is has something to do with autorelease, but I was not able to add a retain like NSArray *data_seg = [[datarow objectAtIndex:0] retain]

When I run the code, I get [__NSCFString count]: unrecognized selector sent to instance 0x9d1ad50

Any help is appreciated, I'm not good at programming, and I am very new.

Answer 1

componentsSeparatedByString method returns an NSArray of NSString. Every item that you extract from datarow array is an NSString and an NSString doesn't respond to 'count'. Your code starting at //fill arrays is incorrect. Every objectAtIndex call will return an NSString*.

This is another way of saying that the datatype for data_seg is NSString* (not NSArray*).

Answer 2

With the corrected code snippet, the problem is because data_seg is a string, and -count is not a method of NSString. It seems you think data_seg is an NSArray.

Look at the documentation for -[NSString componentsSeparatedByString:] and see what it returns -- strings! So you get back an array of strings. So what you want is:

NSString *data_seg = [datarow objectAtIndex:0]; //segment number
NSLog(@"my segment number is: %@", data_seg);