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Singleton: How should it be used
...ngleton if:
You need to have one and only one object of a type in system
Do not use a Singleton if:
You want to save memory
You want to try something new
You want to show off how much you know
Because everyone else is doing it (See cargo cult programmer in wikipedia)
In user interface widgets
It ...
Why exactly is eval evil?
...reasons why one should not use EVAL.
The main reason for beginners is: you don't need it.
Example (assuming Common Lisp):
EVALuate an expression with different operators:
(let ((ops '(+ *)))
(dolist (op ops)
(print (eval (list op 1 2 3)))))
That's better written as:
(let ((ops '(+ *)))
(dol...
Why do we need Abstract factory design pattern?
...n inheritance. I may be mistaken, though, as I'm currently travelling, and don't have my GoF book with me. What do you mean by "none of them produce a family of related product interfaces"?
– Mark Seemann
Jul 16 '16 at 15:01
...
How do I ignore a directory with SVN?
I just started using SVN, and I have a cache directory that I don't need under source control. How can I ignore the whole directory/folder with SVN?
...
Cast List to List
...
What is the difference between doing the covariance tolist and doing new List<IFruit>(); then a foreach over the original list and adding each item to the IFruit list? In the foreach way... the object reference would be the same, correct? So... if t...
Android: How can I pass parameters to AsyncTask's onPreExecute()?
...
public MyAsyncTask(boolean showLoading) {
super();
// do stuff
}
// doInBackground() et al.
}
Then, when calling the task, do something like:
new MyAsyncTask(true).execute(maybe_other_params);
Edit: this is more useful than creating member variables because it si...
What's the difference(s) between .ToList(), .AsEnumerable(), AsQueryable()?
...s on AsEnumerable and AsQueryable and mention ToList() along the way.
What do these methods do?
AsEnumerable and AsQueryable cast or convert to IEnumerable or IQueryable, respectively. I say cast or convert with a reason:
When the source object already implements the target interface, the source ob...
Declare multiple module.exports in Node.js
...
You can do something like:
module.exports = {
method: function() {},
otherMethod: function() {},
};
Or just:
exports.method = function() {};
exports.otherMethod = function() {};
Then in the calling script:
const myMod...
How do you beta test an iphone app?
...yone that gives me a device, I can run it on theirs, but is there a way to do a limited release via the app store for beta testing?
...
How do I create a SQL table under a different schema?
...d choose New Table...
With the table designer open, open the properties window (view -> Properties Window).
You can change the schema that the table will be made in by choosing a schema in the properties window.
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