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How can I sort arrays and data in PHP?
... sorts low-to-high or reverse ("r"), whether it sorts values or keys ("k") and how it compares values ("nat" vs. normal). See http://php.net/manual/en/array.sorting.php for an overview and links to further details.
Multi dimensional arrays, including arrays of objects
$array = array(
array('foo'...
What is the difference between quiet NaN and signaling NaN?
I have read about floating-point and I understand that NaN could result from operations. But I can't understand what these are concepts exactly. What is the difference between them?
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Why is XOR the default way to combine hashes?
Say you have two hashes H(A) and H(B) and you want to combine them. I've read that a good way to combine two hashes is to XOR them, e.g. XOR( H(A), H(B) ) .
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Regular expression for floating point numbers
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TL;DR
Use [.] instead of \. and [0-9] instead of \d to avoid escaping issues in some languages (like Java).
Thanks to the nameless one for originally recognizing this.
One relatively simple pattern for matching a floating point number is
[+-]?([0-9]...
Swapping column values in MySQL
I have a MySQL table with coordinates, the column names are X and Y. Now I want to swap the column values in this table, so that X becomes Y and Y becomes X. The most apparent solution would be renaming the columns, but I don't want to make structure changes since I don't necessarily have permission...
All falsey values in JavaScript
...ing that they evaluate as false in expressions like if(value) , value ? and !value ?
4 Answers
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Should I return EXIT_SUCCESS or 0 from main()?
...IT_SUCCESS when it succeeds, just for the sake of symmetry.
On the other hand, if the program never signals failure, you can use either 0 or EXIT_SUCCESS. Both are guaranteed by the standard to signal successful completion. (It's barely possible that EXIT_SUCCESS could have a value other than 0, ...
How to check if hex color is “too black”?
...e darkness of a color chosen by a color picker to see if it's "too black", and if so, set it to white. I thought I could use the first characters of the hex value to pull this off. It's working, but it's switching some legitimately "light" colors too.
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Does Python support short-circuiting?
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Yep, both and and or operators short-circuit -- see the docs.
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Most efficient way to create a zero filled JavaScript array?
...ay(len).fill(0);
Not sure if it's fast, but I like it because it's short and self-describing.
It's still not in IE (check compatibility), but there's a polyfill available.
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