In article <1b8tk9-un9....@chris.zbmc.eu>, tinn...@isbd.co.uk wrote: > The function producing the error is:- > > def get_text(self, idx): # override ! > node = self.items[idx] > > a= [ > ", ".join(node.tags), > node.comment, > node.folderName, > cd2rd(node.date), > node.name, > '[' + self.rating_stars[node.rating] + ']' > ] [self.select] > > return a > > > The error occurs when node[] (or at least its members) turn out to be > empty, you get a Traceback that ends with:- > > File "/usr/lib/jbrout/jbrout/listview.py", line 608, in draw_cell > layout.set_text(self.get_text(thumbnail_num)) > File "/usr/lib/jbrout/jbrout.py", line 325, in get_text ", > ".join(node.tags), > TypeError: sequence item 0: expected string, NoneType found > > Now its *probably* something higher up the tree causing the problem > (it's only one particular image in 20 thousand or so that breaks > things) but I really want to just get things working. So, what's the > neatest way to protect the get_text() method from empty data?
Well, you don't describe what get_text() is supposed to return First, you build a list of what I'm guessing are all strings, then you index into it and return one of the values. So, I'm guessing get_text() is supposed to return a string. At a low level, you can certainly fix that by testing to see if self.items[idx] returns what you're expecting (an instance of Node?) and returning an empty string if it's not: > def get_text(self, idx): # override ! > node = self.items[idx] > if not node: > return "" > > a= [ > ", ".join(node.tags), > node.comment, > node.folderName, > cd2rd(node.date), > node.name, > '[' + self.rating_stars[node.rating] + ']' > ] [self.select] > > return a Whether that makes sense in your program, I have no idea. What does it mean for node to be empty? Is this a normal occurrence? If so, then your code needs to deal with properly (the suggest above being just one possible way). Or, is it "impossible" for node to be empty? In that case, that fact that it *is* empty is a bug, and the above suggestion will just hide the bug for one more level and make it that much harder to figure out what's really going on. What you might really want to do is sprinkle your code with "assert node" statements. This will force your program to crash and burn the first time node is empty, which might help you figure out why it is. -- http://mail.python.org/mailman/listinfo/python-list
