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What is a NullReferenceException, and how do I fix it?
.... This means you either set it to null, or you never set it to anything at all.
Like anything else, null gets passed around. If it is null in method "A", it could be that method "B" passed a null to method "A".
null can have different meanings:
Object variables which are uninitialized and hence poi...
What does enumerate() mean?
...ieving that; one using itertools.count() to do the counting, the other manually counting in a generator function:
from itertools import count
def enumerate(it, start=0):
# return an iterator that adds a counter to each element of it
return zip(count(start), it)
and
def enumerate(it, sta...
Is the C# static constructor thread safe?
... {
mutex.WaitOne();
return instance;
}
// Each call to Acquire() requires a call to Release()
public static void Release()
{
mutex.ReleaseMutex();
}
}
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What's the Linq to SQL equivalent to TOP or LIMIT/OFFSET?
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Technically, the questioner asked for Linq to SQL, so VB is a viable assumption. That said, ALassek, i'm a c# guy myself and prefer your answer. :-)
– David Alpert
Oct 10 '08 at 16:51
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Interface defining a constructor signature?
...ult in Google some 7 years later, I thought I would chip in here - specifically to show how you could use an abstract base class in tandem with your existing Interface and maybe cut down on the amount of refactoring needed in the future for similar situations. This concept has already been hinted a...
Find a private field with Reflection?
...
You can do it just like with a property:
FieldInfo fi = typeof(Foo).GetField("_bar", BindingFlags.NonPublic | BindingFlags.Instance);
if (fi.GetCustomAttributes(typeof(SomeAttribute)) != null)
...
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In Python, using argparse, allow only positive integers
... return ivalue
parser = argparse.ArgumentParser(...)
parser.add_argument('foo', type=check_positive)
This is basically just an adapted example from the perfect_square function in the docs on argparse.
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How to implement an abstract class in ruby?
I know there is no concept of abstract class in ruby. But if at all it needs to be implemented, how to go about it? I tried something like...
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How to initialize all members of an array to the same value?
... array in C (not C++ if that makes a difference). I want to initialize all members of the same value.
23 Answers
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What is the id( ) function used for?
... Python objects.
Is it the same with memory addresses in C?
Conceptually, yes, in that they are both guaranteed to be unique in their universe during their lifetime. And in one particular implementation of Python, it actually is the memory address of the corresponding C object.
If yes, wh...