Data Manipulation with R Book

Preface     V
Data in R     1
Modes and Classes     1
Data Storage in R     2
Testing for Modes and Classes     7
Structure of R Objects     7
Conversion of Objects     8
Missing Values     10
Working with Missing Values     10
Reading and Writing Data     13
Reading Vectors and Matrices     13
Data Frames: read.table     15
Comma- and Tab-Delimited Input Files     17
Fixed-Width Input Files     17
Extracting Data from R Objects     18
Connections     23
Reading Large Data Files     25
Generating Data     27
Sequences     27
Random Numbers     29
Permutations     30
Random Permutations     30
Enumerating All Permutations     30
Working with Sequences     31
Spreadsheets     33
The RODBC Package on Windows     33
The gdata Package (All Platforms)     34
Saving and Loading R Data Objects     35
Working with Binary Files     36
Writing R Objects to Files in ASCII Format     38
The write Function     38
The write.table function     39
Reading Data from Other Programs     39
R and Databases     43
A Brief Guide to SQL     43
Navigation Commands     43
Basics of SQL     44
Aggregation     45
Joining Two Databases     46
Subqueries     47
Modifying Database Records     48
ODBC     49
Using the RODBC Package     50
The DBI Package     51
Accessing a MySQL Database     51
Performing Queries     52
Normalized Tables     52
Getting Data into MySQL     53
More Complex Aggregations     55
Dates     57
as.Date     57
The chron Package     59
POSIX Classes     60
Working with Dates     63
Time Intervals     64
Time Sequences     65
Factors     67
Using Factors     67
Numeric Factors     70
Manipulating Factors     70
Creating Factors from Continuous Variables     72
Factors Based on Dates and Times      73
Interactions     74
Subscripting     75
Basics of Subscripting     75
Numeric Subscripts     75
Character Subscripts     75
Logical Subscripts     76
Subscripting Matrices and Arrays     77
Specialized Functions for Matrices     81
Lists     82
Subscripting Data Frames     83
Character Manipulation     87
Basics of Character Data     87
Displaying and Concatenating Character Strings     87
Working with Parts of Character Values     89
Regular Expressions in R     90
Basics of Regular Expressions     91
Breaking Apart Character Values     93
Using Regular Expressions in R     94
Substitutions and Tagging     98
Data Aggregation     101
table     101
Road Map for Aggregation     106
Mapping a Function to a Vector or List     107
Mapping a function to a matrix or array     110
Mapping a Function Based on Groups     113
The reshape Package     120
Loops in R     126
Reshaping Data     131
Modifying Data Frame Variables     131
Recoding Variables     132
The recode Function     134
Reshaping Data Frames     135
The reshape Package     140
Combining Data Frames     142
Under the Hood of merge     146
Index     149