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Can a decorator of an instance method access the class?
I have something roughly like the following. Basically I need to access the class of an instance method from a decorator used upon the instance method in its definition.
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Python's equivalent of && (logical-and) in an if-statement
... different name in Python.
The logical operators && and || are actually called and and or.
Likewise the logical negation operator ! is called not.
So you could just write:
if len(a) % 2 == 0 and len(b) % 2 == 0:
or even:
if not (len(a) % 2 or len(b) % 2):
Some additional information (...
Why use Abstract Base Classes in Python?
...emented classes.
Long version
There is a contract between a class and its callers. The class promises to do certain things and have certain properties.
There are different levels to the contract.
At a very low level, the contract might include the name of a method or its number of parameters.
In a s...
Why do people use __(double underscore) so much in C++
...specific, and are slightly more detailed than some others have suggested.
All identifiers that contain a double underscore or start with an underscore followed by an uppercase letter are reserved for the use of the implementation at all scopes, i.e. they might be used for macros.
In addition, all ...
PATH issue with pytest 'ImportError: No module named YadaYadaYada'
I used easy_install to install pytest on a mac and started writing tests for a project with a file structure likes so:
20 A...
Convert sqlalchemy row object to python dict
...of a SQLAlchemy object, like the following::
for u in session.query(User).all():
print u.__dict__
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Accessing class variables from a list comprehension in the class definition
...ing a newly created local namespace and the original global namespace. (Usually, the suite contains only function definitions.) When the class’s suite finishes execution, its execution frame is discarded but its local namespace is saved. [4] A class object is then created using the inheritance lis...
How to read a (static) file from inside a Python package?
...
[added 2016-06-15: apparently this doesn't work in all situations. please refer to the other answers]
import os, mypackage
template = os.path.join(mypackage.__path__[0], 'templates', 'temp_file')
s...
Remove all occurrences of a value from a list?
...on over the filter+lambda; the former is more readable in addition to generally more efficient.
– habnabit
Jul 21 '09 at 4:28
17
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Catching an exception while using a Python 'with' statement
... print 'oops'
If you want different handling for errors from the open call vs the working code you could do:
try:
f = open('foo.txt')
except IOError:
print('error')
else:
with f:
print f.readlines()
...