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import math
import asyncio
import logging, sys
import sqlite3
from asyncio import sleep
from logging.handlers import TimedRotatingFileHandler

import aiohttp_cors
import aiosqlite
import socketio

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# -*- coding: utf-8 -*-
"""
Created on Sun Jan 31 11:03:57 2013
 
@author: Sukhbinder
https://sukhbinder.wordpress.com/2022/08/21/principal-component-analysis-with-numpy/
"""
 
 
import numpy as np

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How to use semaphores in asyncio

A short example showing asyncio semaphores

import asyncio
import time
from random import random

async def my_coroutine(sem,task_id):

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Create postgres user and database

How to create a user, a database and grant all privileges on the new database?

sudo -u postgres psql
postgres=# CREATE DATABASE mydb;
postgres=# CREATE USER myuser WITH ENCRYPTED PASSWORD 'mypass';
postgres=# GRANT ALL PRIVILEGES ON DATABASE mydb TO myuser;
postgres=# GRANT ALL ON SCHEMA public TO myuser;

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Install latest version

sudo apt install postgresql-16 postgresql-client-16

List clusters

sudo pg_lsclusters

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Creating GPG keys and subkeys

There are the steps to create GPG key pair and the additional steps to create a subkey.

Create GPG keys

gpg --full-generate-key
Please select what kind of key you want:

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# taken from here: http://web.archive.org/web/20110527163743/https://svn.enthought.com/enthought/browser/sandbox/docs/coding_standard.py

""" This module is an example of the Enthought Python coding standards.

It was adapted from the Python Enhancement Proposal 8 (aka PEP 8) titled
'Style Guide for Python Code' (http://www.python.org/peps/pep-0008.html).

The first item in a module must be a documentation string (docstring).  The
first line of the docstring should be a one line summary.  If a more
detailed description is required, put an empty line before it.

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