python - Pickled file won't load on Mac/Linux

Question

I have an application that imports data from a pickled file. It works just fine in Windows but Mac and Linux behaviour is odd.

In OS X, the pickled file (file extension ".char") is unavailable as a selection unless I set the file type to *.*. Then, if I select a file that has the .char extension, it won't load, giving the error

unpickle_file = cPickle.load(char_file) 

ValueError: could not convert string to float

However, if I create a file that doesn't have the .char extension, that file will load up just fine.

In Linux, when I use the "file open" dialog, my pickled files aren't visible, whether or not they have a file extension. However, I can see them under Nautilus or Dolphin. They simply don't exist to my application though.

---

Edit Here's the save code:

def createSaveFile(self):
        """Create the data files to be saved and save them.

        Creates a tuple comprised of a dictionary of general character information
        and the character's skills dictionary."""
        if self.file_name:
            self.save_data = ({'Name':self.charAttribs.name,

              <snip> 

                self.charAttribs.char_skills_dict)
            self.file = open(self.file_name, 'w')
            cPickle.dump(self.save_data, self.file)
        self.file.close()

Here's the open code:

 def getCharFile(self, event): # wxGlade: CharSheet.<event_handler>
        """Retrieve pickled character file from disk."""
        wildcard = "Character files (*.char) | *.char | All files (*.*) | *.*"        
        openDialog = wx.FileDialog(None, "Choose a character file", os.getcwd(),
        "", wildcard, wx.OPEN | wx.CHANGE_DIR)
        if openDialog.ShowModal() == wx.ID_OK:
            self.path = openDialog.GetPath()
        try:
            char_file =  open(self.path, "r")
            unpickle_file = cPickle.load(char_file)
            char_data, char_skills = unpickle_file
            self.displayCharacter(char_data, char_skills)
        except IOError:
            self.importError = wx.MessageDialog(self, 
            "The character file is not available!",
            "Character Import Error", wx.OK | wx.ICON_ERROR)
            self.importError.ShowModal()
            self.importError.Destroy()
            openDialog.Destroy()

Answer 1

Probably you didn't open the file in binary mode when writing and/or reading the pickled data. In this case newline format conversion will occur, which can break the binary data.

To open a file in binary mode you have to provide "b" as part of the mode string:

char_file = open('pickle.char', 'rb')