Intro fun & speedé à Python

29/10/2015

Intro

• Tim, Game developper
• "Python, not for me"
• Deux ans
• Deux bières

Python not in the browser but everywhere!

Python on the web

Everywhere else

• sysadmin (linux distribs)
• desktop app
• big data / science
• 3d

How ?

Python is fast for you !

You know python !

def filter(values, max):
    results = list()
    for val in values:
        if val < max:
            results.append(val)
    return results

class Test(object):
    def do_something(self, a, b):
        return a + b

Easy to learn, read & write

“I came to Python (...) because it was the best pseudocode. Python has the edge (with a large number of students) when the main goal is communication, not programming per se.”

“Python has the philosophy of making sensible compromises that make the easy things very easy, and don't preclude too many hard things.” Norvig

• only in two ends.

First step

• get python
• get pip & venv
• get ipython
• Experiment & read a lot of code
• Communicate

Semantics

• everything is an object
• only names, values
• runtime is your friend (repl, no compilation)

Fractal & setup

Let's do it!

• requirements.txt
• setup
• fractal
• best practice

Web Stuff

• a bit of http
• wsgi
• flask, bottle, django
• sqlalchemy
• celery

 Flask in a slide

from flask import Flask

app = Flask(__name__)

@app.route('/')
def index():
    return "hello world"

if __name__ == "__main__":
    app.run(host="0.0.0.0", debug=True)

Par rapport aux autres languages ?

JS : celui qui s'en fout

• arguments
• types
• context (this)
• no class, no module, etc.

C#/Java : l'administration soviétique

• utile dans des projets critiques
• mais lent dans la conception, car verbeux & contraignant

Python :

• bon équilibre entre les deux
• fortement typé
• mais dynamique
• la preuve : très gros projets (django, openstack, etc)

In [48]: "1.0" + 1
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
/home/lionel/<ipython-input-48-6f0b01de9b7a> in <module>()
----> 1 "1.0" + 1

TypeError: cannot concatenate 'str' and 'int' objects

Un vrai design de langage

• module, classe, closures
• list comprehension
• magic method
• decorator
• iterator

== ECMA6, 15 ans plus tôt !

Vers l'infini et au delà

• cython : python compilé vers du C (fast!)
• numpy, opengl : 3d and big arrays
• opencv : traitement d'image
• ast manipulation : meta-programming, lisp macros

Et puis Python vers js 😛

• brython
• pypy.js

Conclusion

• partout
• rapide
• simple
• utile

Merci à

• @dungeon_dave
• @francois_jourde
• dfi
• @porteneuve
• l'équipe BdN

Questions