Unlike string formatter, formatter() method is consistent with no change in method call.

In old style you cannot give positional index, but in format() you can.

Padding and aligning strings

These operations are not even available in old style, to choose a character for padding! :)

There are tons of these examples for format(), like thousand separator and so. Go for it and explore more.

Having local git repository server is easy enough by using docker and open source git lab project:

docker pull gitlab/gitlab-ce

#gitlab #open_source #docker

After pulling image into docker repository run the image using the command below:

sudo docker run --detach \
    --hostname gitlab.example.com \
    --publish 443:443 --publish 80:80 --publish 22:22 \
    --name gitlab \
    --restart always \
    --volume /srv/gitlab/config:/etc/gitlab \
    --volume /srv/gitlab/logs:/var/log/gitlab \
    --volume /srv/gitlab/data:/var/opt/gitlab \
    gitlab/gitlab-ce:latest

Reference:
https://docs.gitlab.com/omnibus/docker/README.html

#gitlab #docker #image #docker_run

Communicate by Telegram bot API by using the most used python library: python-telegram-bot.

Send file, message, audio, image and reply easily by using telegram python library:

https://github.com/python-telegram-bot/python-telegram-bot

#telegram #bot #python #library

A complete reference to the documentation on readthedocs:

https://python-telegram-bot.readthedocs.io/en/stable/

#reference #telegram #bot #readthedocs #python

You may have used JSFiddle to interactively write JS code and get instant result. It is good to note that there is one for Database (MySQL, PostgreSQL, SQLite)!
If you want to query, create table, create partition and all the different operations on a database you can do now by using the below site without ever making a big mistake on your system:

https://www.db-fiddle.com/

#mysql #postgresql #database #fiddle #dbfiddle

When you commit to git, then you push and get rejected:

$ git push
 To my_repo:~/my_project.git
  ! [rejected]        dev -> dev (fetch first)
 error: failed to push some refs to 'my_repo:~/my_project.git'
 hint: Updates were rejected because the remote contains work that you do
 hint: not have locally. This is usually caused by another repository pushing
 hint: to the same ref. You may want to first integrate the remote changes
 hint: (e.g., 'git pull ...') before pushing again.
 hint: See the 'Note about fast-forwards' in 'git push --help' for details.

To prevent merging with your local and making your git history filthy, reset head to the latest commit (head~1):

$ git reset HEAD~1
 Unstaged changes after reset:
 M   another_file_here.py
 M   some_file_here.py

Now git pull and the commit again and push. The world is cleaner now.

#git #reset_head #merge #repository

If you are working with #Cement, #Flask or other python frameworks that do not give ODM (Object Document Mapper) out of the box, you can use MongoEngine for MongoDB.
It has all the capabilities that you can almost imagine for an ODM to define schema and apply restrictions to it. You'll hear more about it later.

https://github.com/MongoEngine/mongoengine

#mongodb #mongoengine #ODM #python #ORM

Merging 2 wave files using scipy, audiolab:

import audiolab, scipy
a, fs, enc = audiolab.wavread('file1.wav')
b, fs, enc = audiolab.wavread('file2.wav')
c = scipy.vstack((a,b))
audiolab.wavwrite(c, 'file3.wav', fs, enc)

any and all in python

#any #all #python

Sample code:

any([False, True, True, True, False])
True
any([False, True, True, False, False])
True
all([True, True, False, True, False])
False
all([True, True, True, True, True])
True
any([False, False, False, False, False])
False

#python #any #all

#python #any #all #iterable

In couchDB you have to plan for views beforehand. As you go along, data will grow and it would be a cumbersome task to change views and wait for data reindexing.

In order to implement a view in couchDB you write JS code. For writing view you have to at least have a map function (reduce can be ignored).

An example of a view to get users by their corresponding uid:

function(doc) {
     if (doc.type == "user")
         emit(doc.user_id, doc);
 }

Here we pass doc which is database documents to our function and check if type of document is user (type field is added it is not related to couchDB view), we will emit (let's say return) user document. It's key is user_id and it's value will be user document.

#view #couchdb

You can create different hosts on your ssh config (~/.ssh/config) in order to prevent typing username and password all time and speedup working with remote servers.

A sample host on ssh config:

Host your_server_name
      HostName 192.168.12.182
          User my_user_name_on_remote_server
          Port 22
          IdentityFile ~/.ssh/id_rsa

Now save the config file and exit. You can now ssh to server as below:

ssh your_server_name

INSTEAD OF USING:

ssh my_user_name_on_remote_server@192.168.12.182

#linux #sysadmin #ssh

InfluxDB is time series database that can store huge amount of data for different metrics like CPU, RAM, Storage usage. If you have Grafana in place, one of the databases that would work with it is InfluxDB.

If you setup InfluxDB you can type influx and hit enter to see InfluxDB console (like MySQL):

infladmin@my_host:~$ influx
 Connected to http://localhost:8086 version 1.2.2
 InfluxDB shell version: 1.2.2

Databases in InfluxDB are called well Database :) and tables are called Measurement. To see list of all databases and make a database active do as below:

> SHOW DATABASES
 name: databases
 name
 ----
 _internal
 my_db
 monitoring
 some_other_db

 > USE my_db
 Using database my_db

You are now on my_db database. To display list of measurements (table) and query it:

> SHOW MEASUREMENTS
 name: measurements
 name
 ----
 cpu_stat
 mem_stat

 > SELECT * FROM cpu_stat LIMIT 2;
 name: cpu_stat
 time                my_tag      metric         value
 ----                ----------- ------         -----
 1503999476000000000 CPU_CORE3   CORES            0
 1503999476000000000             total            16

Yes, it is almost similar to MySQL. The main point of such a database is to use monitoring tool in place and push metrics into influxDB, then make graphs by using Grafana.

#influxdb #grafana #measurement #time_series_db

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