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Can a decorator of an instance method access the class?
...omething like this (warning: untested code).
def class_decorator(cls):
for name, method in cls.__dict__.iteritems():
if hasattr(method, "use_class"):
# do something with the method and class
print name, cls
return cls
def method_decorator(view):
# mark the...
What is the meaning of “__attribute__((packed, aligned(4))) ”
...
Before answering, I would like to give you some data from Wiki
Data structure alignment is the way data is arranged and accessed in computer memory. It consists of two separate but related issues: data alignment and data str...
How does python numpy.where() work?
..., True], dtype=bool)`
This is done by overloading the "__gt__" method. For instance:
>>> class demo(object):
def __gt__(self, item):
print item
>>> a = demo()
>>> a > 4
4
As you can see, "a > 4" was valid code.
You can get a full list and docume...
How do I create a namespace package in Python?
...s useful when you want to release related libraries as separate downloads. For example, with the directories Package-1 and Package-2 in PYTHONPATH ,
...
Importing modules from parent folder
...
For me this answer has worked out. However, to make it more explicit, the procedure is to import sys and then sys.path.append("..\<parent_folder>")
– BCJuan
Nov 20 '19 at 16:12
...
How to get the return value from a thread in python?
...ain thread:
import concurrent.futures
def foo(bar):
print('hello {}'.format(bar))
return 'foo'
with concurrent.futures.ThreadPoolExecutor() as executor:
future = executor.submit(foo, 'world!')
return_value = future.result()
print(return_value)
...
Bulk insert with SQLAlchemy ORM
...hemy docs
With these operations, you can now do bulk inserts or updates!
For instance, you can do:
s = Session()
objects = [
User(name="u1"),
User(name="u2"),
User(name="u3")
]
s.bulk_save_objects(objects)
s.commit()
Here, a bulk insert will be made.
...
Getting number of elements in an iterator in Python
...
No. It's not possible.
Example:
import random
def gen(n):
for i in xrange(n):
if random.randint(0, 1) == 0:
yield i
iterator = gen(10)
Length of iterator is unknown until you iterate through it.
...
Cannot kill Python script with Ctrl-C
...blem - once the main thread has started your threads, there's nothing else for it to do. So it exits, and the threads are destroyed instantly. So let's keep the main thread alive:
import time
while True:
time.sleep(1)
Now it will keep print 'first' and 'second' until you hit Ctrl+C.
Edit: as...
python: How do I know what type of exception occurred?
...e care to do none of those things, it's OK to catch the generic exception. For instance, you could provide information about the exception to the user another way, like:
Present exceptions as dialogs in a GUI
Transfer exceptions from a worker thread or process to the controlling thread or process ...