Format contents of NSMutableArray for .csv file - ios

Question

I have a picture slideshow app which allows the user to rate 3 images. The ratings get stored in a NSMutableArray called rated like this:
2014-01-06 07:10:23.040 SlideShowSurvey[50425:70b] (
1, <-- Rating for Picture 1
2, <-- Rating for Picture 2
3 <-- Rating for Picture 3
)
This is then saved to a .csv file using the following code:
-(void)saveRatings
{
NSString *picRatings = [NSString stringWithFormat:#"%#, \n",self.rated];
// Find documents directory
NSString *docPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *survey = [docPath stringByAppendingPathComponent:#"pictureRatings.csv"];
// Create new file if none exists
if (![[NSFileManager defaultManager] fileExistsAtPath:survey])
{
[[NSFileManager defaultManager] createFileAtPath:survey contents:nil attributes:nil];
}
NSFileHandle *fileHandle = [NSFileHandle fileHandleForUpdatingAtPath:survey];
[fileHandle seekToEndOfFile];
[fileHandle writeData:[picRatings dataUsingEncoding:NSUTF8StringEncoding]];
[fileHandle closeFile];
}
I can then display the results of the .csv file to a UITextView, though it displays it exactly how the array is structured. For example, multiple results display as:
(
1,
2,
3
),
(
1,
2,
3
),
(
1,
2,
3
)
Is there a way I am able to format the array so that it is saved as 1,2,3? And would I be able to add a column header like Picture 1, Picture 2, Picture 3? For example, I would like to display results on the UITextView something like:
Picture 1, Picture 2, Picture 3
1,2,3
1,2,3
1,2,3
I've tried searching but can't seem to find this answer. Any help is appreciated! Thanks.
Edit: I have solved this thanks to jrturton's solution, using the following code:
// Set column titles for .csv
NSArray *columnTitleArray = #[#"Picture 1", #"Picture 2", #"Picture 3"];
NSString *columnTitle = [columnTitleArray componentsJoinedByString:#","];
NSString *columnTitleToWrite = [columnTitle stringByAppendingString:#"\n"];
// Separate ratings into cells
NSString *picRatings = [rated componentsJoinedByString:#","];
NSString *picRatingsToWrite = [picRatings stringByAppendingString:#"\n"];
// Find documents directory
..
Then adding this to the method to make sure column headers are only set when a new file is created:
// Create new file if none exists
if (![[NSFileManager defaultManager] fileExistsAtPath:survey])
{
[[NSFileManager defaultManager] createFileAtPath:survey contents:nil attributes:nil];
// Set title for new file
NSFileHandle *fileHandle = [NSFileHandle fileHandleForUpdatingAtPath:survey];
[fileHandle writeData:[columnTitleToWrite dataUsingEncoding:NSUTF8StringEncoding]];
}
..

Answer 1

Here is a much easier way:
NSMutableString *csv = [NSMutableString string];
NSString *label = ...;
[csv appendFormat:#"%#,\n", label];
NSNumber *keyNum = ...;
[csv appendFormat:#"%d,%d\n", [keyNum intValue], [countNum intValue]];
NSString *filename = #"counts.csv";
NSError *error;
[csv writeToFile:filename atomically:YES encoding:NSUTF8StringEncoding error:&error];

Answer 2

NSMutableString *csv = [NSMutableString string];
NSString *label = #"\n";
[csv appendFormat:#",", label];
NSString *picRatings = [rated componentsJoinedByString:csv];
I'm not sure what you expect appendFormat to be doing in the above code, this will probably be raising a warning since label is not used. You don't need a mutable string in this case either.
To get the contents of an array separated by commas, do this:
NSString *picRatings = [rated componentsJoinedByString:#","];
You also need to add a new line to the end of this string, so you'd want:
NSString *picRatingsToWrite = [picRatings stringByAppendingString:#"\n"];
Write this string to your file and you should be fine.

Answer 3

use this parser and get the data into array and look how you can use data into UITabelViewCell https://github.com/davedelong/CHCSVParser