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Unique BooleanField value in Django?
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Whenever I've needed to accomplish this task, what I've done is override the save method for the model and have it check if any other model has the flag already set (and turn it off).
class Character(models.Model):
name = models.CharField(max_length=255)
is_the_chosen_one ...
Can we have multiple in same ?
...e. There are other uses of course, but as far as applicable examples, this one is the most common one for me.
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Why does a base64 encoded string have an = sign at the end
...a base64 encoded string doesn't always end with a =, it will only end with one or two = if they are required to pad the string out to the proper length.
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Difference in make_shared and normal shared_ptr in C++
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The difference is that std::make_shared performs one heap-allocation, whereas calling the std::shared_ptr constructor performs two.
Where do the heap-allocations happen?
std::shared_ptr manages two entities:
the control block (stores meta data such as ref-counts, type-e...
How to find the kth smallest element in the union of two sorted arrays?
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As @JohnKurlak mentioned it doesn't work for values where whole a is smaller than b see repl.it/HMYf/0
– Jeremy S.
Apr 17 '17 at 16:29
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What is the syntax rule for having trailing commas in tuple definitions?
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Assuming that started as a 2 element list that was later extended it has gone wrong in a perhaps not immediately obvious way. Always include the trailing comma and you avoid that trap.
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Shell one liner to prepend to a file
...ms to overcome", "works for me"). If we take your disclaimer seriously, no one should use your hack - and I agree. So what are we left with? A noisy distraction. I see two options: (a) delete your answer, or (b) turn it into a cautionary tale that explains why - tempting as it may be - this approach...
Test if lists share any items in python
I want to check if any of the items in one list are present in another list. I can do it simply with the code below, but I suspect there might be a library function to do this. If not, is there a more pythonic method of achieving the same result.
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One-line list comprehension: if-else variants
...for x in seq ]
and in your second example, the expression is a "complex" one, which happens to involve an if-else.
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How to skip over an element in .map()?
...d seem weird if a couple of cities were completely missing, a mapping from one list to another only really makes sense when there's a 1 to 1 set of result values.
I'm not saying that it doesn't make sense to create a new list from an old list with some values excluded. I'm just trying to make clear ...