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List of Big-O for PHP functions
After using PHP for a while now, I've noticed that not all built-in PHP functions are as fast as expected. Consider these two possible implementations of a function that finds if a number is prime using a cached array of primes.
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Refresh a page using PHP
How can I refresh a page using PHP periodically? If I can not do it by PHP, what is the best recommended scenario?
13 Answe...
MySql server startup error 'The server quit without updating PID file '
...r_computer_name.local.err
It's probably problem with permissions
check if any mysql instance is running
ps -ef | grep mysql
if yes, you should stop it, or kill the process
kill -9 PID
where PID is the number displayed next to username on output of previous command
check ownership of...
How to do an instanceof check with Scala(Test)
...; replacing all JUnit tests with ScalaTests. At one point, I want to check if Guice's Injector injects the correct type. In Java, I have a test like this:
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How do I test a private function or a class that has private methods, fields or inner classes?
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Useful if you don't know the API perhaps, but if you are having to test private methods in this manner there is something up with your design. As another poster says unit testing should test the class's contract: if the contract is too broad and ...
What is the performance of Objects/Arrays in JavaScript? (specifically for Google V8)
...;
var lastLongI = 1;
for(var i=0;i<10000;i++)
{
var before = Date.now();
for(var j=0;j<arrayCount;j++)
dynamicArrays[j][i] = i;
var span = Date.now() - before;
if (span > 10)
{
console.log(i + ": " + span + "ms" + " " + (i / lastLongI));
lastLongI =...
Rails :include vs. :joins
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.joins will just joins the tables and brings selected fields in return. if you call associations on joins query result, it will fire database queries again
:includes will eager load the included associations and add them in memory. :includes loads all the included tables attributes. If you call ...
Select mySQL based only on month and year
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If you have
$_POST['period'] = "2012-02";
First, find the first day of the month:
$first_day = $_POST['period'] . "-01"
Then this query will use an index on Date if you have one:
$q = "
SELECT *
FROM project...
Mac OS X Terminal: Map option+delete to “backward delete word”
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On Yosemite, this is setting is now under Preferences -> Profiles -> Keyboard. Looks like you have to change/set it for each profile.
– palimpsestor
Mar 9 '15 at 21:08
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How is this fibonacci-function memoized?
...!!99, the 100th slot in the list gets "fleshed out", holding the number 99 now, ready for next access.
That is what that trick, "going-through-a-list", is exploiting. In normal doubly-recursve Fibonacci definition, fib n = fib (n-1) + fib (n-2), the function itself gets called, twice from the top,...