data wrangling lab - university of arkansas at little rock...why do we choose python? •c or c++...

Data Wrangling Lab

Sept 26-29, 2016 (c) 2016 iCDO@UALR 1

David /WEI DAI

CDO-1 Certificate Program:Foundations for Chief Data Officers

Agenda

• Basic Python Program

• MongoDB Lab

• Clean Data Lab

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A Tutorial on the Python Programming Language

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Why do we choose Python?

• C or C++

• Java

• Perl

• Scheme

• Fortran

• Python

• Matlab

Modern, interpreted, object-oriented, full featured high level programming language

Portable(Unix/Linux,MacOS X,Windows) Open source, intellectual property rights held

by the Python Software Foundation Python versions: 2.x and 3.x

3.x is not backwards compatible with 2.x This course uses 3.x version

Fast program development Simple syntax Easy to write well readable code Large standard library Lots of third party libraries

Numpy, Scipy, Biopython MatplotlibSept 26-29, 2016 (c) 2016 iCDO@UALR 4

Python Program Platform

• Open a browser and access the website:

• https://teslae.host.ualr.edu:8888

• Password: python

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Hello World

•At the prompt type “ hello world!”

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The print and string Statement

>>> print('hello')hello>>> print('hello', David')hello David

• Elements separated by commas print with a space between them

• Strings are immutable

• “+” is overloaded to do concatenation >>> x = 'hello'

>>> x = x + ' America'>>> print(x)'hello America'

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Substrings and Methods

>>> s = '012345'>>> print(s[3])'3'>>> print(s[1:4])'123'>>> print(s[2:])'2345'>>> print(s[:4])'0123'>>> print(s[-2])'4'

• len(String) – returns the number of characters in the String

• str(Object) – returns a String representation of the Object

>>> print(len(s))6>>> print(str(10.3))'10.3'

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• Relational operators== equal

!=, <> not equal

> greater than

>= greater than or

equal

< less than

<= less than or equal

• Logical operatorsand and

or or

notnot

Variables

• Are not declared, just assigned

• The variable is created the first time you assign it a value

• Assignment is = and comparison is ==

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Lists

• Ordered collection of data

• Data can be of different types

• Lists are mutable

• Issues with shared references and mutability

• Same subset operations as Strings

>>> x = [1,'hello', (3 + 2j)]>>> print(x)[1, 'hello', (3+2j)]>>> print(x[2])(3+2j)>>> print(x[0:2])[1, 'hello']

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Lists: Modifying Content

• x[i] = a reassigns the ith element to the value a

• Since x and y point to the same list object, both are changed

• The method appendalso modifies the list

>>> x = [1,2,3]>>> y = x>>> x[1] = 15>>>print( x)[1, 15, 3]>>> print(y)[1, 15, 3]>>> x.append(12)>>> print(y)[1, 15, 3, 12]

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Lists: Modifying Contents

• The method append modifies the list and returns None

• List addition (+) returns a new list

>>> x = [1,2,3]>>> y = x>>> z = x.append(12)>>> print(z == None)True>>> print(y)[1, 2, 3, 12]>>> x = x + [9,10]>>> print(x)[1, 2, 3, 12, 9, 10]>>> print(y)[1, 2, 3, 12]>>>

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If ELSE Statements

if expression:statement(s)

else:statement(s)

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For Loops

• Similar to perl for loops, iterating through a list of values

16123

for x in [1,6,12,3] :print(x)forloop1.py

0123

for x in range(4) :print(x)forloop2.py

range(N) generates a list of numbers [0,1, …, n-1]Sept 26-29, 2016 (c) 2016 iCDO@UALR 15

Functions are first class objects

• Can be assigned to a variable

• Can be passed as a parameter

• Can be returned from a function

• Functions are treated like any other variable in Python, the def statement simply assigns a function to a variable

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Function Basics

def min(x,y) :if x > y :

return xelse :

return y

>>> mix(2,5)5

functionbasics.py

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Python for graph

• Matplotlib is a python 2D plotting library which produces high quality figures

• Read demos is ready at plot_demo.ipy file.

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MongoDB LAB

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http://teslae.host.ualr.edu:8081

username: mongotest

Password: mongotest

MongoDB Express User Interface

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MongoDB Express

• MongoDB Express is Web-based MongoDB admin interface

• You can create, review, export, delete data through the platform

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MongoDB Express Lab

• Export cities.json

• Add a new city name which you like to MongoDB

• Query or find the new city name

• Delete the new city name

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Clean Data Lab

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Courses Data in MongoDB

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Connect to MongoDB

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CRUD Operation for MongoDB

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Basic Python-MongoDB Lab

• Write codes to add a new course • {"courseid": "71XX", <--Change XX

• "subject": "information science",

• "title": "data quality algorithm", <--Change course name

• "hours": 3 <--Change hours

• }

• Write codes to search your courses• query = {"title": "data quality algorithm" } <--Change title name

• projection = {"hours": 3 <--Change hours

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Basic Python-MongoDB lab (cont.)

• A challenge project• Write codes to add your name at teachers’ list

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Clean Data lab (cont.)

• Teachers, Courses, and Students are MDM data so that the data is accurate and trust.

• student_course_report and

• teacher_course_report contain incorrect data, but teacherid, studentid ,and courseid are correct.

Teachersinfo teacher_course_report

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Clean Data lab (cont.)

teacher_course_report

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Clean Data lab (cont.)

• Write codes to clean student_course_report

• Tips:

coursesinfo

studentsinfo

student_course_report

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Clean Data lab (cont.)

• A challenge project• Write codes to clean t_s_c_report.

coursesinfo

studentsinfo

TeachersinfoSept 26-29, 2016 (c) 2016 iCDO@UALR 32

THANK YOU

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Reference

• http://www.scipy-lectures.org/packages/statistics/index.html

• https://github.com/mongo-express/mongo-express

• https://api.mongodb.com/python/current/

• https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&sqi=2&ved=0ahUKEwjI-uufkabPAhVOgx4KHdWsAXwQFggiMAE&url=http%3A%2F%2Fwww.fh.huji.ac.il%2F~goldmosh%2FPythonTutorialFeb152012.ppt&usg=AFQjCNH5nWz_PAanbl7JCdE6PN7SFUVxyw&sig2=SGxL0rIqfL8gbxQD7mfURA

• https://docs.mongodb.com/manual/

• http://www2.imm.dtu.dk/pubdb/views/edoc_download.php/5944/pdf

• O'higgins, Niall. MongoDB and Python: Patterns and processes for the popular document-oriented database. " O'Reilly Media, Inc.", 2011.

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