04. Data

[briatte]

• 4.0 Basic data operators
  • (Tidy) data frames, glimpse, rename and select, mutate, recode
  • Plain text, read_lines, stringr functions
  • JSON with jsonlite (or NDJSON)
  • XML/HTML trees with xml2
• 4.1 Imports and Exports
  • Files
  • Databases
  • Files from Outer Space: Downloading a Google Spreadsheet
  • Files from Outer Space: Web Scraping with httr and rvest (and xm2)
• 4.2. Reshapes and aggregates (N.B. things below are really case studies)
  • Split-Apply-Combine and tidiness
  • Reshaping: long and wide (always prefer long)
  • Aggregating (aggregate, group_by, summarise), slicing (apply, slice etc.)
  • Coercing to, and binding, data frames
    • possible example: Facebook data
• 4.3. Practice
  • Currently: Estimates of Congressional ideology
  • >> MOVED from 4.2. Visualizing the U.S. housing market by city (Case Schiller Index)
  • >> MOVED from 4.2. Visualizing U.S. homicide trends by weapon type

TODO:

• Include Twitter API example.

Notes:

• Complex data object structures should be covered in Section 02 'Objects'