senemaktas / Python-Programming

Flask , Django , APIs and so on ....

Python-Coding

To run Python programs on the Linux terminal:

• Open termnal CTRL+ALT+T
• Update the packages list: sudo apt update
• Install Python3 : sudo apt-get install python3
• Create a folder on computer to use for Python programs, such as ~/pythonpractice
• Type cd ~/pythonpractice to change directory to your pythonpractice folder.
• Open text editor and create the python file for example: nano hello.py or gedit hello.py and save program in that folder.
• Make sure the first line of file has, add #! and the path of the Python interpreter #!/usr/bin/env python.
• Make the script executable by chmod +x <filename>.py.
• And run it as ./<filename>.py.For example: ./hello.py .
• python <filename>.py for Python 2.x python3 <filename>.py for Python 3.x

Create virtual environment

• First install this : pip3 install virtualenv

• Open a folder and go to inside it. And create an envirenoment inside of your folder: virtualenv env

• Activate the environment (for GNU/Linux and Mac): source env/bin/activate (for Windows) : \env\Scripts\activate.bat

• When your virtual env is active create requirement file for dependencies: pip freeze > requirements.txt

• See the txt file : cat requirements.txt

• İnstall the all necessary packages : pip install -r requirements.txt

  Basics	Intermediate	Advanced
  - variables,numbers,strings,lists	- exceptions handling	- multithreading
  - dictionary , tuple	- classes , objects	- multiprocessing
  - if,for control blocks	- inheritance	- multiprocessing lock & pool
  - functions	- generators	- unit tests:pytest
  - read,write files	- list/dict comprehensions	- context managers
  - modules	- sets,command line argparse	- ......
  - .......	- .......	- ......

There are examples with Flask, which is the Python Web Framework:

• Install Flask : pip3 install Flask
• Import : from flask import Flask
• install SQLAlchemy the Database Toolkit for Python: pip3 install flask-sqlalchemy
• Import : from flask_sqlalchemy import SQLAlchemy

Project layout should look like this:
Project_name/
├── templates/
│ └── base.html
└── static/
│ └── style.css
-https://flask.palletsprojects.com/en/1.1.x/tutorial/layout/

Python Debugging With Pdb

• Import : import pdb;
• Insert the following code at the location where you want to break into the debugger: pdb.set_trace()

Something useful

• iterate over files in that directory - from 0 to N. frame!!!!for filename in os.listdir(directory):

import os
import re
directory = '/images' # assign directory
for data_file in sorted(os.listdir(directory), key=lambda x:float(re.findall("(\d+)",x)[0])):
  print(data_file)