Community Data Science Workshops (Spring 2014)/Saturday May 3rd lecture

Lecture Outline

API
- definition of an API in general
- definition of web API for data
Review material from last session
- variables, different types
- printing
- if statements
- lists
- dictionaries
- for loops
- modules
- example python program
New programming concepts:
- urllib2 and urlopen
- interpolate variables into a string using % and %()s
- JSON file (JavaScript Object Notation)
  - what is json
  - import json; json.loads()
  - like Python (except no single quotes)
  - simple lists, dictionaries
  - can reflect more complicated data structures
- Example file at http://mako.cc/cdsw.json
- open a file and write to it
placekitten.com
- API that takes specially crafted URLs and gives appropriately sized picture of kittens
- example of placekitten in browser
  - kittens of different sizes
  - kittens in greyscale or color
- show how to use place
- write a small program to grab arbitrary square from placekitten by asking for the size on standard in
Wikipedia API
- explain MediaWiki, exists on other wikis
- navigate to api page and show the documentation, point out examples
- looking at the images within a page http://en.wikipedia.org/w/api.php?action=query&titles=Seattle&prop=images&imlimit=20&format=jsonfm
- looking at within two pages http://en.wikipedia.org/w/api.php?action=query&titles=Seattle%7CBellevue,_Washington&prop=images&imlimit=50&format=jsonfm
- edit count http://en.wikipedia.org/w/api.php?action=query&list=users&ususers=Benjamin_Mako_Hill%7CJtmorgan%7CSj%7CMindspillage&usprop=editcount&format=jsonfm
- give me the content of the main page http://en.wikipedia.org/w/api.php?format=json&action=query&titles=Main%20Page&prop=revisions&rvprop=content
Other APIs
- every API is different, so read the documentation!
- rate limiting
- authenticaiton
- text encoding issues