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What is an idempotent operation?
... idempotent operation is one that has no additional effect if it is called more than once with the same input parameters. For example, removing an item from a set can be considered an idempotent operation on the set.
In mathematics, an idempotent operation is one where f(f(x)) = f(x). For example, ...
Private vs Protected - Visibility Good-Practice Concern [closed]
...of thumb is: make everything as private as possible. This makes your class more encapsulated, and allows for changing the internals of the class without affecting the code using your class.
If you design your class to be inheritable, then carefully choose what may be overridden and accessible from...
Haskell, Lisp, and verbosity [closed]
...-order function (and I include monads, arrows, etc.), but it might require more thinking (but only the first time, and it's fun and you'll be a better programmer for it), and
the static system is sufficiently general that it never gets in your way, and somewhat surprisingly it actually "aids in achi...
Why are quaternions used for rotations?
...ions are used in practice. Euler angles use the least memory; matrices use more memory but don't suffer from Gimbal lock and have nice analytical properties; and quaternions strike a nice balance of both, being lightweight, but free from Gimbal lock.
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How can I use UUIDs in SQLAlchemy?
...wise, you will have the same scalar value for all instances of this class. More details here:
A scalar, Python callable, or ColumnElement expression representing the default value for this column, which will be invoked upon insert if this column is otherwise not specified in the VALUES clause of...
Is it better to call ToList() or ToArray() in LINQ queries?
...you should use ToList. In the majority of scenarios ToArray will allocate more memory than ToList.
Both use arrays for storage, but ToList has a more flexible constraint. It needs the array to be at least as large as the number of elements in the collection. If the array is larger, that is not...
PHP: Storing 'objects' inside the $_SESSION
...query them from the DB each time, you are using state. HTTP is stateless (more or less; but see GET vs. PUT) but almost everything anybody cares to do with a web app requires state to be maintained somewhere. Acting as if pushing the state into nooks and crannies amounts to some kind of theoretica...
Best Practice for Forcing Garbage Collection in C#
...i (msdn.microsoft.com/en-us/library/…). This gives the garbage collector more information about your system without interfering with the collection algorithms.
– Govert
Feb 1 '12 at 18:51
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HTML text input allow only numeric input
... Allow digits and '.' only, using a RegExp
});
See the JSFiddle demo for more input filter examples. Also note that you still must do server side validation!
TypeScript
Here is a TypeScript version of this.
function setInputFilter(textbox: Element, inputFilter: (value: string) => boolean): v...
Declare slice or make slice?
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In addition to fabriziom's answer, you can see more examples at "Go Slices: usage and internals", where a use for []int is mentioned:
Since the zero value of a slice (nil) acts like a zero-length slice, you can declare a slice variable and then append to it in a loop:...