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Unique (non-repeating) random numbers in O(1)?
...esn't resort to something like an O(N) search of previous values to do it. Is this possible?
22 Answers
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What is a covariant return type?
What is a covariant return type in Java? In object-oriented programming in general?
9 Answers
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Android 4.3 Bluetooth Low Energy unstable
...gy (testing on the Nexus 4). After getting started with the official BLE APIs in Android 4.3, I have noticed that after I connect a device for the first time I am rarely able to successfully connect to / communicate with that device or any other device again.
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How to call an external command?
...cess
subprocess.run(["ls", "-l"])
The advantage of subprocess vs. system is that it is more flexible (you can get the stdout, stderr, the "real" status code, better error handling, etc...).
The official documentation recommends the subprocess module over the alternative os.system():
The subpr...
How can I replace a newline (\n) using sed?
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Use this solution with GNU sed:
sed ':a;N;$!ba;s/\n/ /g' file
This will read the whole file in a loop, then replaces the newline(s) with a space.
Explanation:
Create a label via :a.
Append the current and next line to the pa...
Singletons vs. Application Context in Android?
Recalling this post enumerating several problems of using singletons
and having seen several examples of Android applications using singleton pattern, I wonder if it's a good idea to use Singletons instead of single instances shared through global application state (subclassing android.os.Applicat...
A semantics for Bash scripts?
...e formal introduction to Bash as a programming language. For example: What is the evaluation order? what are the scoping rules? What is the typing discipline, e.g. is everything a string? What is the state of the program -- is it a key-value assignment of strings to variable names; is there more tha...
What is the difference between == and equals() in Java?
I wanted to clarify if I understand this correctly:
23 Answers
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Which CheckedListBox event triggers after a item is checked?
I have a CheckedListBox where I want an event after an item is checked so that I can use CheckedItems with the new state.
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How do browsers pause/change Javascript when tab or window is not active?
...ce tests that need to detect if people are paying attention or not. But, this question is not about the page visibility API .
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