One way to do it would be with variadic argument unpacking: def foo(…, **kwargs): … if math.isclose(x, y, **kwargs): … This would allow you to specify atol and rtol as keyword arguments to the main function foo, which it would then pass on unchanged to math.isclose. However, I would also say that it is idiomatic … Read more
Since the bytecode is unlikely to change regardless of how many times it is compiled, the interpreter can take advantage of the small speedup gain. Unless you are very short of hard drive space, you should select this option.
As you note, you can store the items to delete somewhere and defer the deletion of them until later. The problem then becomes when to purge them and how to make sure that the purge method eventually gets called. The answer to this is a context manager which is also a subclass of dict. class … Read more
There are two different characters involved here. One is the MICRO SIGN, which is the one on the keyboard, and the other is GREEK SMALL LETTER MU. To understand what’s going on, we should take a look at how Python defines identifiers in the language reference: identifier ::= xid_start xid_continue* id_start ::= <all characters in … Read more
From the http.server docs: CGIHTTPRequestHandler can be enabled in the command line by passing the –cgi option: $ python3 -m http.server –bind localhost –cgi 8000 Put your script into cgi_directories: This defaults to [‘/cgi-bin’, ‘/htbin’] and describes directories to treat as containing CGI scripts. Open in the browser: $ python -mwebbrowser http://localhost:8000/cgi-bin/hello.py where hello.py: #!/usr/bin/env … Read more
What solved the problem for me was to restart my kernel, import the following first: import matplotlib matplotlib.use(‘TKAgg’) Then, import matplotlib.pyplot as plt You probably imported matplotlib with another framework before you tried to change to TKAgg. Restart your kernel.
There’s a raise_from in python-future; simply install it pip install future and import to use from future.utils import raise_from # or: from six import reraise as raise_from class FileDatabase: def __init__(self, filename): try: self.file = open(filename) except IOError as exc: raise_from(DatabaseError(‘failed to open’), exc) UPDATE The compatibility package six also supports raise_from, from version 1.9 … Read more
Not really, it’s just an odd way of making it not raise an error when called via the class: MyClass.call_me() works fine since, even though nothing is implicitly passed as with instances, the default value for that argument is provided. If no default was provided, when called, this would of course raise the TypeError for … Read more
When you are not interested in some values returned by a function we use underscore in place of variable name . Basically it means you are not interested in how many times the loop is run till now just that it should run some specific number of times overall.
For an OrderedDict it’s inherently O(n) because the ordering is recorded in a linked list. For the builtin dict, there’s a vector (a contiguous array) rather than a linked list, but pretty much the same thing in the end: the vector contains a few kind of “dummies”, special internal values that mean “no key has … Read more