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If strings are immutable in .NET, then why does Substring take O(n) time?
...mory location.
The simple .substring(...) shares the internally used char array with the original String object, which you then with new String(...) can copy to a new array, if needed (to avoid hindering garbage collection of the original one).
I think this kind of flexibility is a best option for...
How to get a cross-origin resource sharing (CORS) post request working
...cess-Control-Max-Age: 604800');
header("Content-type: application/json");
$array = array("ok" => $_POST["x"]);
echo json_encode($array);
This is the only way I know to truly POST cross-domain from JS.
JSONP converts the POST into GET which may display sensitive information at server logs.
...
How to crop an image in OpenCV using Python
... then:
roi = im[y1:y2, x1:x2]
here is a comprehensive resource on numpy array indexing and slicing which can tell you more about things like cropping a part of an image. images would be stored as a numpy array in opencv2.
:)
...
Focus Next Element In Tab Index
...Element && document.activeElement.form) {
var focussable = Array.prototype.filter.call(document.activeElement.form.querySelectorAll(focussableElements),
function (element) {
//check for visibility while always include the current activeElement
return ...
How do I create test and train samples from one dataframe with pandas?
...
@kuatroka np.random.rand(len(df)) is an array of size len(df) with randomly and uniformly distributed float values in range [0, 1]. The < 0.8 applies the comparison element-wise and stores the result in place. Thus values < 0.8 become True and value >= 0.8...
Split string to equal length substrings in Java
...
Here's the regex one-liner version:
System.out.println(Arrays.toString(
"Thequickbrownfoxjumps".split("(?<=\\G.{4})")
));
\G is a zero-width assertion that matches the position where the previous match ended. If there was no previous match, it matches the beginning of t...
Best practices to test protected methods with PHPUnit
...elf::getMethod('foo');
$obj = new MyClass();
$foo->invokeArgs($obj, array(...));
...
}
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How to remove the lines which appear on file B from another file A?
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NR==FNR{a[$0];next} idiom is for storing the first file in an associative array as keys for a later "contains" test.
NR==FNR is checking whether we're scanning the first file, where the global line counter (NR) equals to the current file line counter (FNR).
a[$0] adds the current line to the associ...
Polymorphism in C++
...ing inlining and dead code elimination, loop unrolling, static stack-based arrays vs heap)
__FILE__, __LINE__, string literal concatenation and other unique capabilities of macros (which remain evil ;-))
templates and macros test semantic usage is supported, but don't artificially restrict how that ...
JavaScript: How to pass object by value?
...to o.
Also, if obj has a property that references another object, like an Array, you'll need to be sure to shadow that object before adding members to the object, otherwise, those members will be added to obj, and will be shared among all objects that have obj in the prototype chain.
var o = {
...