The ‘\r’ character is the carriage return, and the carriage return-newline pair is both needed for newline in a network virtual terminal session. From the old telnet specification (RFC 854) (page 11): The sequence “CR LF”, as defined, will cause the NVT to be positioned at the left margin of the next print line (as would, for example, the … Read more
You can change the property categorie of the class Article like this: and the error should disappear. Eventually you might need another option for on_delete, check the documentation for more details: EDIT: As you stated in your comment, that you don’t have any special requirements for on_delete, you could use the option DO_NOTHING:
Use GroupBy.sum:
There is an ordered set (possible new link) recipe for this which is referred to from the Python 2 Documentation. This runs on Py2.6 or later and 3.0 or later without any modifications. The interface is almost exactly the same as a normal set, except that initialisation should be done with a list. This is a MutableSet, so the … Read more
Do-something if <condition>, else do-something else.
You can use the + operator to combine them: Output:
You can use the round function, which takes as its first argument the number and the second argument is the precision after the decimal point. In your case, it would be:
I would check that the file is not empty first: Also open(target, ‘a’).close() is doing nothing in your code and you don’t need to use ;.
Use urllib.request.urlopen(): This is the most basic way to use the library, minus any error handling. You can also do more complex stuff such as changing headers. On Python 2, the method is in urllib2:
This works in Python 2.x. For Python 3 look in the docs: