I'm having success when I use this code to get a string from an array of file names called "fileList":

cell.timeBeganLabel.text = [[[self.fileList objectAtIndex:[indexPath row]] lastPathComponent] stringByDeletingPathExtension];

so I expected the same code to generate the same string as a key for me in this:

NSDictionary *stats = [thisRecordingsStats objectForKey:[[[self.fileList objectAtIndex:[indexPath row]] lastPathComponent] stringByDeletingPathExtension]];
  cell.durationLabel.text = [stats objectForKey:@"duration"];

or this:

NSDictionary *stats = [thisRecordingsStats objectForKey:@"%@",[[[self.fileList objectAtIndex:[indexPath row]] lastPathComponent] stringByDeletingPathExtension]];

Both build without error, and the log shows my data is there: but I'm getting a blank UILabel.
Have I not written the dynamic key generator correctly?