In 2006 I had taken a bunch of film photos and had them processed by shutterfly. Shutterfly also scanned these photos and put them in my account so I was happy. Finally this year I decided I wanted the scans on my computer and I ordered a DVD of them (you can't download the hi-res versions from the website). I was unpleasantly surprised when I got the scans back. They are 270 ppi or so, amounting to 1536x1024 from 35mm film. I would have expected something more detailed from them such as 2000 ppi or so. But it was a bad surprise as some of the photos were landscapes and I was looking forward to enlargements. I guess I'll have to dig out the negatives from the boxes.
Python's context managers are a very neat way of handling code that needs a teardown once you are done. Python objects have do have a destructor method ( __del__ ) called right before the last instance of the object is about to be destroyed. You can do a teardown there. However there is a lot of fine print to the __del__ method. A cleaner way of doing tear-downs is through Python's context manager , manifested as the with keyword. class CrushMe: def __init__(self): self.f = open('test.txt', 'w') def foo(self, a, b): self.f.write(str(a - b)) def __enter__(self): return self def __exit__(self, exc_type, exc_val, exc_tb): self.f.close() return True with CrushMe() as c: c.foo(2, 3) One thing that is important, and that got me just now, is error handling. I made the mistake of ignoring all those 'junk' arguments ( exc_type, exc_val, exc_tb ). I just skimmed the docs and what popped out is that you need to return True or...
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