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Why use Abstract Base Classes in Python?
...igher-level, semantic promises in the contract.
For example, if there is a __str__() method, it is expected to return a string representation of the object. It could delete all contents of the object, commit the transaction and spit a blank page out of the printer... but there is a common understand...
How to include PHP files that require an absolute path?
...
This should work
$root = realpath($_SERVER["DOCUMENT_ROOT"]);
include "$root/inc/include1.php";
Edit: added imporvement by aussieviking
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How do I check which version of NumPy I'm using?
...c Rodger: yeah, but your is more general to any module that cares to set a __version__.
– Esteban Küber
Oct 5 '09 at 14:13
57
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How can I use “sizeof” in a preprocessor macro?
....
Following snippets will produce no code if sizeof(someThing) equals PAGE_SIZE; otherwise they will produce a compile-time error.
1. C11 way
Starting with C11 you can use static_assert (requires #include <assert.h>).
Usage:
static_assert(sizeof(someThing) == PAGE_SIZE, "Data structure do...
Creating C macro with ## and __LINE__ (token concatenation with positioning macro)
...PASTE2(x, y) TOKENPASTE(x, y)
#define UNIQUE static void TOKENPASTE2(Unique_, __LINE__)(void) {}
Then, __LINE__ gets expanded to the line number during the expansion of UNIQUE (since it's not involved with either # or ##), and then the token pasting happens during the expansion of TOKENPASTE.
It ...
Can a dictionary be passed to django models on create?
...our model is called MyModel:
# create instance of model
m = MyModel(**data_dict)
# don't forget to save to database!
m.save()
As for your second question, the dictionary has to be the final argument. Again, extra and extra2 should be fields in the model.
m2 =MyModel(extra='hello', extra2='world'...
Python: How do I make a subclass from a superclass?
...
# Initialize using Parent
#
class MySubClass(MySuperClass):
def __init__(self):
MySuperClass.__init__(self)
Or, even better, the use of Python's built-in function, super() (see the Python 2/Python 3 documentation for it) may be a slightly better method of calling the parent for ...
Asking the user for input until they give a valid response
...rsed.
while True:
try:
# Note: Python 2.x users should use raw_input, the equivalent of 3.x's input
age = int(input("Please enter your age: "))
except ValueError:
print("Sorry, I didn't understand that.")
#better try again... Return to the start of the loop
...
difference between variables inside and outside of __init__()
...
Variable set outside __init__ belong to the class. They're shared by all instances.
Variables created inside __init__ (and all other method functions) and prefaced with self. belong to the object instance.
...
Get __name__ of calling function's module in Python
....stack()[1]
mod = inspect.getmodule(frm[0])
print '[%s] %s' % (mod.__name__, msg)
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