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Is a Java hashmap search really O(1)?
...o? Unless these hashmaps are vastly different from any of the hashing algorithms I was bought up on, there must always exist a dataset that contains collisions.
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What's the best way to communicate between view controllers?
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These are good questions, and its great to see that you're doing this research and seem concerned with learning how to "do it right" instead of just hacking it together.
First, I agree with the previous answers which focus on the importance of putting da...
Reset Entity-Framework Migrations
I've mucked up my migrations, I used IgnoreChanges on the initial migration, but now I want to delete all my migrations and start with an initial migration with all of the logic.
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must appear in the GROUP BY clause or be used in an aggregate function
... this issue, you must calculate the aggregate in a sub-query and then join it with itself to get the additional columns you'd need to show:
SELECT m.cname, m.wmname, t.mx
FROM (
SELECT cname, MAX(avg) AS mx
FROM makerar
GROUP BY cname
) t JOIN makerar m ON m.cname = t.cname AND t.mx...
Would you, at present date, use JBoss or Glassfish (or another) as Java EE server for a new project?
... do need them, then that removes several of your options including my favorite, Jetty.
Do you have to use any of the other major J2EE technologies like JMS, ESB, etc? If so, and you really can't do without, then you are again constrained to a full-blown J2EE container. Carefully think and investi...
Creating an empty list in Python
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Here is how you can test which piece of code is faster:
% python -mtimeit "l=[]"
10000000 loops, best of 3: 0.0711 usec per loop
% python -mtimeit "l=list()"
1000000 loops, best of 3: 0.297 usec per loop
However, in practice, this initialization is most likely an extremely small part of you...
Java: when to use static methods
I am wondering when to use static methods? Say if I have a class with a few getters and setters, a method or two, and I want those methods only to be invokable on an instance object of the class. Does this mean I should use a static method?
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Why does auto a=1; compile in C?
...ause local scope is the default for a variable declared inside a function, it's also the same as int a in this example.
This keyword is actually a leftover from C's predecessor B, where there were no base types: everything was int, pointer to int, array of int.(*) Declarations would be either auto ...
What does the “map” method do in Ruby?
... |n| n * n } #=> [1, 4, 9]
Array and Range are enumerable types. map with a block returns an Array. map! mutates the original array.
Where is this helpful, and what is the difference between map! and each? Here is an example:
names = ['danil', 'edmund']
# here we map one array to another, c...
Various ways to remove local Git changes
I just cloned a git repository and checked out a branch. I worked on it, and then decided to remove all my local changes, as I wanted the original copy.
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