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How are Python's Built In Dictionaries Implemented?
...keys' hashes. You can think of it like this:
hash key dict_0 dict_1 dict_2...
...010001 ffeb678c 633241c4 fffad420 ...
... ... ... ... ...
For a 64 bit machine, this could save up to 16 bytes per key per extra dictionary.
Shared Keys for...
How to get current CPU and RAM usage in Python?
...#!/usr/bin/env python
import psutil
# gives a single float value
psutil.cpu_percent()
# gives an object with many fields
psutil.virtual_memory()
# you can convert that object to a dictionary
dict(psutil.virtual_memory()._asdict())
# you can have the percentage of used RAM
psutil.virtual_memory().pe...
Comma in C/C++ macro
...ose the macro argument in parentheses:
FOO((std::map<int, int>), map_var);
The problem is then that the parameter remains parenthesized inside the macro expansion, which prevents it being read as a type in most contexts.
A nice trick to workaround this is that in C++, you can extract a typ...
How to divide flask app into multiple py files?
...eate a sub-component of your app as a Blueprint in a separate file:
simple_page = Blueprint('simple_page', __name__, template_folder='templates')
@simple_page.route('/<page>')
def show(page):
# stuff
And then use it in the main part:
from yourapplication.simple_page import simple_page
...
How do the likely/unlikely macros in the Linux kernel work and what is their benefit?
...
Let's decompile to see what GCC 4.8 does with it
Without __builtin_expect
#include "stdio.h"
#include "time.h"
int main() {
/* Use time to prevent it from being optimized away. */
int i = !time(NULL);
if (i)
printf("%d\n", i);
puts("a");
return 0;
}
...
If isset $_POST
...
Since !empty() is already checks for both, you can use this:
if (!empty($_POST["mail"])) {
echo "Yes, mail is set";
} else {
echo "No, mail is not set";
}
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How do I get the filepath for a class in Python?
...u can use the inspect module, like this:
import inspect
inspect.getfile(C.__class__)
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SASS - use variables across multiple files
...his:
I have a folder named utilities and inside that I have a file named _variables.scss
in that file i declare variables like so:
$black: #000;
$white: #fff;
then I have the style.scss file in which i import all of my other scss files like this:
// Utilities
@import "utilities/variables";
/...
What are the rules about using an underscore in a C++ identifier?
...r parameters. If you've come from an MFC background, you'll probably use m_foo . I've also seen myFoo occasionally.
5 An...
java get file size efficiently
...m access is one of the major responsibilities of an OS. faqs.org/docs/linux_admin/buffer-cache.html To get good benchmarking results, the cache should be cleared before each run.
– z0r
Jul 6 '12 at 0:16
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