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When are you truly forced to use UUID as part of the design?
...UID, the timestamp is incremented by 1. Collisions should not occur unless one of the following happens: The MAC address is spoofed; One machine running two different UUID generating applications produces UUIDs at the exact same moment; Two machines without a network card or without user level acces...
Finish an activity from another activity
I want to finish one activity from another activity, like:
10 Answers
10
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Should I implement __ne__ in terms of __eq__ in Python?
...oes not imply that x!=y
is false. Accordingly, when defining
__eq__(), one should also define __ne__() so that the operators will behave as expected.
In a lot of cases (such as this one), it will be as simple as negating the result of __eq__, but not always.
...
What is the memory consumption of an object in Java?
Is the memory space consumed by one object with 100 attributes the same as that of 100 objects, with one attribute each?
12...
How do I sort one vector based on values of another
...
Here is a one liner...
y[sort(order(y)[x])]
[edit:] This breaks down as follows:
order(y) #We want to sort by y, so order() gives us the sorting order
order(y)[x] #looks up the sorting order for each x
sort(ord...
Why does modern Perl avoid UTF-8 by default?
... stdout, and stderr to UTF‑8. Both these are global effects, not lexical ones.
At the top of your source file (program, module, library, dohickey), prominently assert that you are running perl version 5.12 or better via:
use v5.12; # minimal for unicode string feature
use v5.14; # optimal for u...
What do 3 dots next to a parameter type mean in Java?
...ny of the following:
myMethod(); // Likely useless, but possible
myMethod("one", "two", "three");
myMethod("solo");
myMethod(new String[]{"a", "b", "c"});
Important Note: The argument(s) passed in this way is always an array - even if there's just one. Make sure you treat it that way in the method ...
How exactly does a generator comprehension work?
...king them into list, it waits, and yields each item out of the expression, one by one.
>>> my_list = [1, 3, 5, 9, 2, 6]
>>> filtered_list = [item for item in my_list if item > 3]
>>> print(filtered_list)
[5, 9, 6]
>>> len(filtered_list)
3
>>> # compar...
What is “Orthogonality”?
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From Eric S. Raymond's "Art of UNIX programming"
Orthogonality is one of the most important properties that can help make even complex designs compact. In a purely orthogonal design, operations do not have side effects; each action (whether it's an API call, a macro invocation, or a languag...
Which is faster: multiple single INSERTs or one multiple-row INSERT?
I am trying to optimize one part of my code that inserts data into MySQL. Should I chain INSERTs to make one huge multiple-row INSERT or are multiple separate INSERTs faster?
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