This document provides an introduction to learning Python using Flask through a workshop organized by PyLadies Malaysia. It covers the strengths of Python, basics of Python programming including data types, control structures, and collections, as well as practical usage of Flask for web development. The workshop includes hands-on practice with quizzes and examples to reinforce learning.

1. learning
python with flask
P Y L A D I E S 2 0 1 7 W O R K S H O P # 1
MALAYSIA

2. before we start

3. why
pyladies
M A L A Y S I A
MALAYSIA

4. how
pyladies
W O R K S
MALAYSIA

5. pyladies
need you!
B E P A R T O F T H E H I S T O R Y M A K E R S
MALAYSIA

7. Just right before we start

8. @OnApp https://facebook.com/OnApp
A SHOUT OUT TO OUR VENUE SPONSOR

9. introduction

10. SIAN LERK LAU
linkedin.com/in/sianlerk
@kiawin

11. ∗ Amateur guitarist
∗ Ex-Intern at OnApp KL
∗ UM undergraduate
student (3rd year)
∗ Python newbie, 8 months
old
FADHIL YAACOB
@sdil

12. a shout out to our
pyladies mentors
ALIES YAP
JANICE SHIU
PEI PEI
MALAYSIA

13. jom!

15. R U
REHDY
TO PYTHON*

16. DO.
* WHY PYTHON
* THE ENVIRONMENT (PART 1 & 2)
* PYTHON 101
* CONTROL STRUCTURES
* A REAL PROGRAM

17. WHY*
CODE IN PYTHON

18. EASY TO UNDERSTAND
CONCISE SYNTAX
MULTI-PURPOSE
STRENGTH OF PYTHON

19. GOOGLE-ABLE!
WELL SUPPORTED LIBS
FAST TO DELIVER
STRENGTH OF PYTHON

20. ENV*
PYTHON ENVIRONMENT (PART 1)

21. # Python interactive shell
$ python
# Python interactive shell
# (on steroid!)
$ pip install ipython
$ ipython
# QUIZ: What version of python
# are you currently using?
ENV* - EASIEST WAY TO PYTHON

22. 101*
PYTHON - DATA TYPES

23. # DECLARE-LESS TYPED
>>> a = 1
>>> print a
1
>>> type(a)
<type 'int'>
101* - DATA TYPES

24. # MORE TYPES - '' and ""
>>> b = 'a'
>>> c = 'abc'
>>> d = "abc"
# QUIZ: WHAT DATA TYPES ARE b, c and d?
>>> type(b)
>>> type(c)
>>> type(d)
101* - DATA TYPES

25. # MORE TYPES
# bool, NoneType, float, long
>>> e = True
>>> f = False
>>> g = None
>>> h = 1.0
>>> i = 1L
# QUIZ: WHAT IS None?
101* - DATA TYPES

26. 101*
PYTHON - COLLECTIONS

27. # COLLECTION 1: LIST
>>> a = [1, 2, 3]
>>> b = list()
>>> b.append(1)
>>> b.append(2)
>>> b.append(3)
# QUIZ: How do we retrieve the value?
# QUIZ: Is a and b same?
101* - DATA TYPES

28. # SAME - EQUALITY or IDENTITY?
>>> a == b
True
>>> a is b
False
# QUIZ: WHAT IS THE DIFF
# BETWEEN == AND is
101* - DATA TYPES

29. # COLLECTION 2 - TUPLE
>>> c = (1, 2, 3)
>>> d = 1, 2, 3
# QUIZ: SO AGAIN, IS c SAME with d?
101* - DATA TYPES

30. # COLLECTION 3: dict
>>> e = {1: 11, 2: 22}
>>> e[1]
>>> e[2]
# QUIZ: IS THIS AN array?
# QUIZ: MUST THE key BE int?
101* - DATA TYPES

31. # COLLECTION 4: set
>>> f = set()
>>> f.add(1)
>>> f.add(2)
>>> f.add(3)
# QUIZ: WHAT IS THE DIFF
# BETWEEN list AND set?
101* - DATA TYPES

32. 101*
PYTHON - CONTROL STRUCTURES

33. 101* - DATA TYPES
# if, else, elif
>>> a = 2
>>> if a == 1:
... print "hello"
... elif a == 2:
... print "world"
>>>

34. 101* - DATA TYPES
# if, else, elif CONTINUES
>>> a = 1
>>> if a == 1:
... print "hello"
... else:
... print "world"
>>>

35. 101* - DATA TYPES
# for LOOP
>>> for i in [1, 2, 3]:
... print i
>>> for j in range(1,3):
... print j
# QUIZ: WHAT DO YOU SEE WHEN print j

36. 101* - DATA TYPES
# for LOOP
>>> for i in (1, 2, 3):
... print i
>>> for k,v in {1: 11, 2: 22}.iteritems():
... print k, v
# QUIZ: WHAT DO YOU SEE WHEN print k, v

37. 101* - DATA TYPES
# list comprehension
>>> a = [1,2,3,4,5]
>>> b = [i+1 for i in a]
# QUIZ: WHAT IS THE VALUE OF b?

38. 101* - DATA TYPES
# list comprehension
>>> a = [1,2,3,4,5]
>>> b = [i for i in a if i % 2 == 0]
# QUIZ: WHAT IS THE VALUE OF b?

39. ENV*
PYTHON ENVIRONMENT (PART 2)

40. pip
∗ Package management system used to install and manage
software packages written in Python
∗ Why?
Easy package installations, updating, configuring and
removals with a single command
∗ Over 86,000 Python packages can be accessed through
PyPI
∗ Sample commands:
$ pip install flask
$ pip uninstall flask

41. python packages
∗ Mathematical Analytics: Numpy
∗ DB Connectors: MySQL, MongoDB,
PostgreSQL, etc.
∗ Web Frameworks: Pyramid, Django
∗ Twitter API client
∗ Many more…
“It’s like Swiss-army toolchain”

42. virtualenv
∗ Is an isolated working copy of Python which allows you to
work on a specific project without worry of affecting other
projects
∗ Why?
We might wants to maintain the package version
(prefer not upgrading it to newer version)
“Do not fix things that aren’t broken”

43. THE BIG PICTURE
Python3
virtualenv1 virtualenv2 virtualenv3
package1 v1
package2 v1
package3 v1
package1 v2
package2 v2
package3 v2
package1 v1
package2 v2
package3 v1

44. virtualenv
# INSTALL VIRTUALENV
$ pip install virtualenv
# CREATE A NEW VENV
$ virtualenv Project1

45. virtualenv
# ACTIVATE A VENV ON LINUX
workon Project1
# ON WINDOWS
$ /path/to/folder/Scripts/activate.bat
# LIST INSTALLED PACKAGES
(test)$ pip freeze

46. PROG*
A REAL PROGRAM, NOW

47. flask
∗ Flask is a micro web framework written in Python
∗ Micro framework means it does not require particular
tools or libraries and it just works
∗ Suitable for minimal website or a full featured website
∗ Many extensions freely available:
User authentications
Flask-Security
File Uploads
Database

48. Let’s get hand dirty
∗ “Hello World!”

49. PROG* - HELLO WORLD!
# INSTALL FLASK MODULE
$ pip install flask
# QUIZ: WHAT DO YOU SEE IN RESULT
# OF THE ABOVE COMMAND

50. PROG* - HELLO WORLD!
# EDIT A NEW FILE USING YOUR FAVOURITE
# TEXT EDITOR
$ vim hello.py

51. PROG* - HELLO WORLD!
# KEY IN THE FOLLOWING INTO THE FILE
from flask import Flask
app = Flask(__name__)
@app.route("/")
def hello():
return "Hello World!"

52. NOOO WAY… R U KIDDING ME?
CONGRATULATIONS!
U HV COMPLETED
A WORKING PROGRAM WEB SERVICE

53. # LET’S START THE WEB SERVICE
$ export FLASK_APP=hello.py
$ flask run
# IF WINDOWS
$ set FLASK_APP=hello.py
$ flask run
# QUIZ: WHAT’S NEXT?
PROG* - HELLO WORLD!

54. localhost:5000
BEAM ME UP, SCOTTY
Hello World!

55. SIMPLICITY
Programming can be easy and fun
(Using python)

56. PROG*
WHAT’S NEXT? MOOOOOOORE~

57. localhost:5000
BEAM ME UP, SCOTTY… AGAIN
Not Hello World!

58. localhost:5000/hello
HECTOR AND THE SEARCH FOR
HAPPINESS
Hello World!

59. PROG* - MOOOOOOORE~
# KEY IN THE FOLLOWING INTO THE FILE
from flask import Flask
app = Flask(__name__)
@app.route("/")
def index():
return "Not Hello World!"
@app.route("/hello")
def hello():
return "Hello World!"
# QUIZ: MUST THE ROUTE NAME SAME WITH
# THE METHOD NAME?

60. PROG* - MOOOOOOOORE~
# QUIZ: CAN I DON’T RESTART FLASK
# EVERY TIME I MODIFY MY FILE?
$ export FLASK_DEBUG=1
$ flask run
# QUIZ: WHAT IS THE COMMAND IF YOU USE
# WINDOWS?

61. PROG* - MOOOOOOORE~
# KEY IN THE FOLLOWING INTO THE FILE
from flask import Flask
app = Flask(__name__)
@app.route("/")
def index():
return "Index!"
@app.route("/user/<username>")
def user(username):
return "Hello %s!" % username
# QUIZ: WHAT HAPPEN WHEN YOU VISIT
# http://localhost:5000/user

62. localhost:5000/user/kiawin
WHO AM I
Hello kiawin!

63. PROG* - MOOOOOOORE~
# FRUIT TIME!
from flask import Flask
app = Flask(__name__)
@app.route("/fruit/<fruit_name>")
def fruit(fruit_name):
if fruit_name in ["durian", "jackfruit"]:
return "Nooooo..."
else:
return "Yummy..."
# QUIZ: WHAT HAPPEN IF YOU VISIT
# http://localhost:5000/

64. localhost:5000/fruit/durian
KING OF FRUITS
Nooooo...

65. localhost:5000/fruit/mangosteen
HOW ABOUT MANGOSTEEN
Yummy...

66. localhost:5000/fruit/DURIAN
WHAT IF?
Nooooo...

67. PROG* - MOOOOOOORE~
# FrUiT TiMe!
from flask import Flask
app = Flask(__name__)
@app.route("/fruit/<fruit_name>")
def fruit(fruit_name):
if fruit_name.lower() in ["durian", "jackfruit"]
return "Nooooo..."
else:
return "Yummy..."

68. STUFF*
SLIDES
slideshare.net/kiawin/learning-python-with-flask
SOURCE
flask.pocoo.org/docs/0.12/quickstart

69. Q&A*
ASK US ANYTHING