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How to make a class JSON serializable
...t;>> magic(f)
'{"fname": "/foo/bar"}'
In that case you can merely call json.dumps(f.__dict__).
If you want more customized output then you will have to subclass JSONEncoder and implement your own custom serialization.
For a trivial example, see below.
>>> from json import JSONE...
Dealing with commas in a CSV file
...any easily-available csv library - that is to say RFC 4180.
There's actually a spec for CSV format and how to handle commas:
Fields containing line breaks (CRLF), double quotes, and commas should be enclosed in double-quotes.
http://tools.ietf.org/html/rfc4180
So, to have values foo and ...
Representing graphs (data structure) in Python
...f._graph[node2].add(node1)
def remove(self, node):
""" Remove all references to node """
for n, cxns in self._graph.items(): # python3: items(); python2: iteritems()
try:
cxns.remove(node)
except KeyError:
pass
tr...
std::enable_if to conditionally compile a member function
... I want to use std::enable_if to choose between two member-functions and allow only one of them to be used.
7 Answers
...
How to implement the --verbose or -v option into a script?
...
def verboseprint(*args):
# Print each argument separately so caller doesn't need to
# stuff everything to be printed into a single string
for arg in args:
print arg,
print
else:
verboseprint = lambda *a: None # do-nothing function
(Yes, y...
How to retrieve a module's path?
...
import a_module
print(a_module.__file__)
Will actually give you the path to the .pyc file that was loaded, at least on Mac OS X. So I guess you can do:
import os
path = os.path.abspath(a_module.__file__)
You can also try:
path = os.path.dirname(a_module.__file__)
To ge...
Speed comparison with Project Euler: C vs Python vs Erlang vs Haskell
... and the time changes to 11.1 seconds
in factorCount' you have needlessly called fromIntegral. A fix results in no change though (the compiler is smart, lucky for you).
You used mod where rem is faster and sufficient. This changes the time to 8.5 seconds.
factorCount' is constantly applying two extr...
What optimizations can GHC be expected to perform reliably?
...has a lot of optimizations that it can perform, but I don't know what they all are, nor how likely they are to be performed and under what circumstances.
...
Is errno thread-safe?
...t errno; so my question is, is it safe to check errno value after some calls or use perror() in multi-threaded code. Is this a thread safe variable? If not, then whats the alternative ?
...
How do I filter ForeignKey choices in a Django ModelForm?
... can populate the validation data by making using the super(...).__init__ call in your overridden method. If you are making several of these queryset changes its a lot more elegant to package them by overriding the init method.
– michael
Aug 7 '09 at 4:53
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