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RuntimeError on windows trying python multiprocessing
...l import (i.e. execute) the main module at start. You need to insert an if __name__ == '__main__': guard in the main module to avoid creating subprocesses recursively.
Modified testMain.py:
import parallelTestModule
if __name__ == '__main__':
extractor = parallelTestModule.ParallelExtrac...
How to “perfectly” override a dict?
...bitrary key-altering
function before accessing the keys"""
def __init__(self, *args, **kwargs):
self.store = dict()
self.update(dict(*args, **kwargs)) # use the free update to set keys
def __getitem__(self, key):
return self.store[self.__keytransform__(key)]...
Python memoising/deferred lookup property decorator
...
from boltons.cacheutils import cachedproperty
class Foo(object):
def __init__(self):
self.value = 4
@cachedproperty
def cached_prop(self):
self.value += 1
return self.value
f = Foo()
print(f.value) # initial value
print(f.cached_prop) # cached property is c...
What is the id( ) function used for?
...d and user does not see them:
class democlass:
classvar = 24
def __init__(self, var):
self.instancevar1 = var
self.instancevar2 = 42
def whoreferencesmylocalvars(self, fromwhere):
return {__l__: {__g__
for __g__ in fromwhere
...
How to implement a good __hash__ function in python [duplicate]
...
__hash__ should return the same value for objects that are equal. It also shouldn't change over the lifetime of the object; generally you only implement it for immutable objects.
A trivial implementation would be to just ret...
What does the “yield” keyword do?
...ou create the method of the node object that will return the generator
def _get_child_candidates(self, distance, min_dist, max_dist):
# Here is the code that will be called each time you use the generator object:
# If there is still a child of the node object on its left
# AND if the d...
Inheritance and Overriding __init__ in python
...his nowadays:
class FileInfo(dict):
"""store file metadata"""
def __init__(self, filename=None):
super(FileInfo, self).__init__()
self["name"] = filename
Note the following:
We can directly subclass built-in classes, like dict, list, tuple, etc.
The super function handle...
What is the purpose of the -m switch?
...s this only works on the subset of modules that are executable i.e. have a __main__.py file. Most don't and will break e.g. python -m sys 'print(sys.version)' fails with python: No code object available for sys. Suggest you make that clear in the answer.
– smci
...
SQL SELECT WHERE field contains words
...
This move was incredible ,, I am Really JEALOUS :( _______________________________________________________________________________________ INNER JOIN (@FilterTable F1 ON T.Column1 LIKE '%' + F1.Data + '%' LEFT JOIN (@FilterTable F2 ON T.Column1 NOT LIKE '%' + F2.Data + ...
How to get a function name as a string?
...
my_function.__name__
Using __name__ is the preferred method as it applies uniformly. Unlike func_name, it works on built-in functions as well:
>>> import time
>>> time.time.func_name
Traceback (most recent ...