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Scheduling recurring task in Android
...es running until the service becomes available.
Note: The Alarm Manager is intended for cases where you want to have your application code run at a specific time, even if your application is not currently running. For normal timing operations (ticks, timeouts, etc) it is easier and much more efficie...
Speed up the loop operation in R
...Radford Neal has done a bunch of optimizations, some of which were adopted into R Core, and many others which were forked off into pqR.
And lastly, if all of the above still doesn't get you quite as fast as you need, you may need to move to a faster language for the slow code snippet. The combina...
Why is it bad style to `rescue Exception => e` in Ruby?
... from everything, including subclasses such as SyntaxError, LoadError, and Interrupt.
Rescuing Interrupt prevents the user from using CTRLC to exit the program.
Rescuing SignalException prevents the program from responding correctly to signals. It will be unkillable except by kill -9.
Rescuing Sy...
Instance variables vs. class variables in Python
... @Devin, yep, I've heard of the Borg pattern, since I'm the one who introduced it (in 2001, cfr code.activestate.com/recipes/… ;-). But there's nothing wrong, in simple cases, with simply having a single instance with no enforcement.
– Alex Martelli
A...
Uses for Optional
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The main point of Optional is to provide a means for a function returning a value to indicate the absence of a return value. See this discussion. This allows the caller to continue a chain of fluent method calls.
This most closely matc...
Pros and cons of AppSettings vs applicationSettings (.NET app.config / Web.config)
... wanted to configure there really is a number - someone could put a string into that setting..... you just access it as ConfigurationManager["(key)"] and then it's up to you to know what you're dealing with.
Also, over time, the <appSettings> can get rather convoluted and messy, if lots of p...
How to filter SQL results in a has-many-through relation
...re-knowledge which clubs will be queried):
ALTER TABLE student ADD CONSTRAINT student_pkey PRIMARY KEY(stud_id );
ALTER TABLE student_club ADD CONSTRAINT sc_pkey PRIMARY KEY(stud_id, club_id);
ALTER TABLE club ADD CONSTRAINT club_pkey PRIMARY KEY(club_id );
CREATE INDEX sc_club_id_idx ON stud...
What is the difference between Serializable and Externalizable in Java?
... performance problem. To handle this situation, the java.io.Externalizable interface was provided, which is like java.io.Serializable but with custom-written mechanisms to perform the marshalling and unmarshalling functions (you need to implement readExternal and writeExternal methods on your class)...
When to use Preorder, Postorder, and Inorder Binary Search Tree Traversal strategies
...s an inherent sequence in the nodes, and you want to flatten the tree back into its original sequence, than an in-order traversal should be used. The tree would be flattened in the same way it was created. A pre-order or post-order traversal might not unwind the tree back into the sequence which w...
When should I use malloc in C and when don't I?
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char *some_memory = "Hello World";
is creating a pointer to a string constant. That means the string "Hello World" will be somewhere in the read-only part of the memory and you just have a pointer to it. You can use the string as read-only. You cannot make changes to it. Exam...