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Best practice for Python assert
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The four purposes of assert
Assume you work on 200,000 lines of code with four colleagues Alice, Bernd, Carl, and Daphne.
They call your code, you call their code.
Then assert has four roles:
Inform Alice, Bernd, Carl, and Daphne what your code expects.
Assume you have a m...
Is a GUID unique 100% of the time?
...8 written out is approximately: 34,028,236,692,093,846,346,337,460,743,177,000,000. Statistically, if you calculated 1000 GUIDs every second, it would still take trillions of years to get a duplicate.
– Entity
Jul 24 '12 at 4:01
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Combining a class selector and an attribute selector with jQuery
... to remove the space. i.e.
$(".myclass[reference=12345]").css('border', '#000 solid 1px');
There is a fiddle here http://jsfiddle.net/xXEHY/
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How do I get an object's unqualified (short) class name?
...tr_replace('\\', '/', static::class));
}
}
$a = new ClassA();
$num = 100000;
$rounds = 10;
$res = array(
"Reflection" => array(),
"Basename" => array(),
"Explode" => array(),
);
for($r = 0; $r < $rounds; $r++){
$start = microtime(true);
for($i = 0; $i < $nu...
Are 2^n and n*2^n in the same time complexity?
...complexity grows is exponential.
So, we consider to be 2ⁿ, 3ⁿ, eⁿ, 2.000001ⁿ, or our n⋅2ⁿ to be same group of complexity with exponential grows.
To give it a bit mathematical sense, we consider a function f(x) to grow (not faster than) exponentially if exists such constant c > 1, tha...
What are the differences between a clustered and a non-clustered index?
...of the records need to be unique is a fallacy. Say you have a table with 1,000,000 rows and you index a column with 500,000 keys. 0% are unique but each key returns 2 out of a million rows. This index is absolutely useful regardless that 0% of the records are unique.
– Stephani...
Using module 'subprocess' with timeout
... "kill", added work-around. BTW, great recipe! I've used this to launch 50,000 buggy processes so far without freezing or crashing the handling wrapper.
– Yaroslav Bulatov
Jul 1 '11 at 21:02
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Migration: Cannot add foreign key constraint
...Blueprint $table) {
// this line throw QueryException "SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint..."
// $table->integer('user_id')->unsigned()->index();
$table->bigInteger('user_id')->unsigned()->index(); // this is working
...
Seeding the random number generator in Javascript
...nswer.)
var seed = 1;
function random() {
var x = Math.sin(seed++) * 10000;
return x - Math.floor(x);
}
You can set seed to be any number, just avoid zero (or any multiple of Math.PI).
The elegance of this solution, in my opinion, comes from the lack of any "magic" numbers (besides 10000...
List of Big-O for PHP functions
...r example the difference between a call to array_key_exists at N=1 and N=1,000,000 is ~50% time increase.
Interesting Points:
isset/array_key_exists is much faster than in_array and array_search
+(union) is a bit faster than array_merge (and looks nicer). But it does work differently so keep that...