Chapter 2 Working with Data

We always need to clean data before working. Even data downloaded from the database is not perfect. Sometimes there are missing data. Moreover, when data are from database, we need to combine them before using.

Learning Objectives:

• Five basic data types (logical, integer, numeric, complex, character)

• Two extended data types (date, factor)

• Five basic data structure (vector, matrix, array, data.frame, list)

• Basic data management

• Advanced data management with dplyr, tidyr, and reshape

• Download world bank data with wbstats

• Import and export external data through csv (comma-delimited) files