Python Bootcamp Slides

7/30/2019 Python Bootcamp Slides

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Python Bootcamp - C4Dlab

SCI labs, University of NairobiNov 24th 2013

Kenny Rachuonyo


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Introduction to Python

Features of Python

Simplicity - pseudocode

Free and Open Source - community

High-level no low-level mngt

Interpreted run from source

Object-Oriented simple to use Extensible C/C++


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Features (cont.)

Embeddable games, graphics,

Extensive Libraries (batteries included) datacompression, OS, Networking, Internet,

Multimedia, Graphics


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Python in the Industry

Web

Google Youtube, backend tasks..

Reddit news aggregation site

Disqus commenting service

Numerous web frameworks django, Zope,webapp2, web.py, pyramid, flask


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Desktop

Games Counterstrike, Civilization IV

Cinema 4D Graphics

Dropbox

GUI frameworks PyGTK, PyQT,


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Scientific Computing

NASA

Packages: Scipy, Numpy, Matplotlib,


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Mobile

Nokia Symbian Series 60

Android Scripting Layer for Android

Blackberry

Kivy cross-platform: iOS, Android, Linux,Windows, Mac


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Python Basics

The interpreter

Installation

Windows (set path)

Datatypes: int, str, float, lists, tuples,dictionaries

Basic I/O


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Python Basics

Variables

Dynamically-typed vs statically-typed

>>> x = 1

>>>y = hello

Strongly-typed

>>> x + y

Type function

>>> type(x) Integer vs float

>>> z = 1.0


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Python Basics

Operator Operation

+ Addition

- Subtraction

/ Division

* Multiplication

** Power

% Modulus


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Python Basics

How will this be evaluated?

>>>X = 1 + 2 3 ** 4 * ( 5+6)


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Python Basics

Operator Precedence rules

Parenthesis

Power

Multiplication

Addition

Left-to-right


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Python Basics

Integer division

>>> 4/2

>>> 5/2

Mixing integer and floats>>> 5/2.0

Casting between integer and floats

>>> float(5)

>>>int(5.0)


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Python Basics

Strings sequence of characters

>>> s = hello world

Looking inside

>>> s[0]

Concatenation

>>> s = hello + world

Finding length

>>> len(s)

Slicing

>>> s = s[0:5]


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Python Basics

Handy String functions

find

>>> s.find('e')

Replace

>>> n = s.replace('e', 'a' )

Make upper, lower

>>> u = s.upper()


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Python Basics

Get the second word 'world' by slicing

>>> hello, world[x:y]


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Python Basics

Lists collection of values

Declaring

>>> l = list()

>>> l = [] Can hold different types

>>> l = [1, 'a', [2, 3], 4]

>>> l[2]

Appending>>> l.append('an item')

>>>del(l[2])


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Python Basics

Lists collection of values

Getting length

>>> len(l)

Slicing

>>> l[1:4]

Converting between strings and lists

>>> strlist = this is a string.split('s')>>> z.join(strlist)


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Python Basics

Append an item to the list within the list

>>> l = [1, 'a', [2, 3], 4]

>>> l = [1, 'a', [2, 3, 5], 4]


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Python Basics

Handy functions

Sum

>>> sum([2, 3, 4])

Max

>>> max([2, 3, 4])

Min

>>> min([2, 3, 4])


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Python Basics

Dictionaries key, value pairs

Associative array, hash table

Declaring

>>> d = dict()

>>> d = {}

Setting a value

>>> d[event] = bootcamp

>>> d = {event : bootcamp }

Getting a value

>>> d[event]


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Python Basics

Mutability

Mutable can change

Lists, dictionary

Immutable cannot change

Strings, tuples

Try set, del..


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Python Basics

Casting numbers and strings

Strings and numbers

>>> int(234)

>>> str(234)


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Python Basics

Importing modules

>>> import math

>>> math.sqrt(4)

>>> from math import sqrt

>>> sqrt(4)

dir() function

>>> dir(math)


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Python Basics

Basic I/O>>> name = raw_input()

>>> name = raw_input(Name: )

Input numbers:>>>age = raw_input(Age: )

>>>age = int(raw_input(Age: ))


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Modules

Interactive mode vs modules

Indentation


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Boolean Values

True

>>> 1 < 2

False

>>> 1 > 2 Also evaluate to False:

, [], {}, 0


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Loops

While loop while condition is truex = 0

while x < 10:

print x

x = x + 1

For loop loops over itemswords = ['this' , 'is', 'a', 'list']

for w in words:

print w

Loop over strings, dictionaries..

Range() function>>> range(3)

>>> range(0, 10, 2)


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Functions Defining functions

def say_hello():

print hello

Calling functions

say_hello() Parameters

def sub(a, b):

s = a - b

return s

sub(b=3, a=2)


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Functions

Commenting in Python

def sub(a, b):

d = a b #subtracts b from a

return d

Doc strings

def sub(a, b):

this functions takes in 2 integers and returns theirdifference

d = a b

return d


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File I/O

Writing to a file

f = open('text.txt', 'wb')

f.write('This is a line.\n')

f.close()

Reading a file

f = open('text.txt', 'rb')

stream = f.read()

f.close()


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Accessing the Web

Establishing a connection

sockets

Requests and Responses

GET, retrieve a webpage

POST, save data

Download a webpage

fopen = urllib.urlopen(http://www.google.com)data = fopen.read()


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Demo

Web demo

Scientific computing


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Next Steps

Intermediate topics: Classes and objects in Python

Regular Expressions

Exceptions etc

Python on Appengine

Python user group


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Resources

Official Python Docs tutorial

http://docs.python.org/2/tutorial/

A byte of Python

http://www.swaroopch.com/notes/python/ Think like a Computer Scientist

http://www.openbookproject.net/thinkcs/python/english2e/
http://docs.python.org/2/tutorial/http://www.swaroopch.com/notes/python/http://www.openbookproject.net/thinkcs/python/english2e/http://www.openbookproject.net/thinkcs/python/english2e/http://www.swaroopch.com/notes/python/http://docs.python.org/2/tutorial/

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