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Test if lists share any items in python
... are stored using a hash table in Python, searching them is O(1) (see here for more information about complexity of operators in Python). Theoretically, this is O(n+m) on average for n and m objects in lists a and b. But 1) it must first create sets out of the lists, which can take a non-negligible ...
What is the difference between char s[] and char *s?
...doesn't have to be in read-only memory (some implementations have no MMUs, for example). The n1362 c1x draft simply states that modifying such an array causes undefined behavior. But +1 anyway, since relying on that behavior is a silly thing to do.
– paxdiablo
...
Writing your own STL Container
...ry should be one of std::input_iterator_tag, std::output_iterator_tag,std::forward_iterator_tag,std::bidirectional_iterator_tag,std::random_access_iterator_tag. Also note that the below is technically more strict than required, but this is the idea. Note that the vast majority of the "standard" func...
Access data in package subdirectory
...
This actually worked for me. Did not have any problems. I am using python 3.6
– Jorge
Jan 4 '19 at 13:07
1
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Is there a decorator to simply cache function return values?
... is periodically called with the same arguments.
Example of an LRU cache for computing Fibonacci numbers:
@lru_cache(maxsize=None)
def fib(n):
if n < 2:
return n
return fib(n-1) + fib(n-2)
>>> print([fib(n) for n in range(16)])
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89...
HTML5 Email Validation
...
In HTML5 you can do like this:
<form>
<input type="email" placeholder="Enter your email">
<input type="submit" value="Submit">
</form>
And when the user press submit, it automatically shows an error message like:
...
Check that an email address is valid on iOS [duplicate]
...rString : laxString;
NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];
return [emailTest evaluateWithObject:checkString];
}
Discussion on Lax vs. Strict - http://blog.logichigh.com/2010/09/02/validating-an-e-mail-address/
And because categories are j...
Can I have onScrollListener for a ScrollView?
...) to it using the method addOnScrollChangedListener().
You can see more information about this class here.
It lets you be aware of every scrolling event - but without the coordinates. You can get them by using getScrollY() or getScrollX() from within the listener though.
scrollView.getViewTreeObs...
What does new self(); mean in PHP?
... same as :
self::$_instance = new MyClass();
Edit : a couple more informations, after the comments.
If you have two classes that extend each other, you have two situations :
getInstance is defined in the child class
getInstance is defined in the parent class
The first situation would lo...
How do I execute inserts and updates in an Alembic upgrade script?
...
What you are asking for is a data migration, as opposed to the schema migration that is most prevalent in the Alembic docs.
This answer assumes you are using declarative (as opposed to class-Mapper-Table or core) to define your models. It shoul...