Preface xiii -- About the Companion Website xvii -- Introduction xix -- 1 Open-Source Tools for Data Science 1 -- 1.1 R Language and RStudio 1 -- 1.2 Python Language and Tools 5 -- 1.3 Advanced Plain Text Editor 8 -- 1.4 CSV Format for Datasets 8 -- 2 Simple Exploratory Data Analysis 13 -- 2.1 Missing Values Analysis 13 -- 2.2 R: Descriptive Statistics and Utility Functions 15 -- 2.3 Python: Descriptive Statistics and Utility Functions 17 -- 3 Data Organization and First Data Frame Operations 23 -- 3.1 R: Read CSV Datasets and Column Selection 24 -- 3.2 R: Rename and Relocate Columns 36 -- 3.3 R: Slicing, Column Creation, and Deletion 38 -- 3.4 R: Separate and Unite Columns 45 -- 3.5 R: Sorting Data Frames 49 -- 3.6 R: Pipe 55 -- 3.7 Python: Column Selection 59 -- 3.8 Python: Rename and Relocate Columns 67 -- 3.9 Python: NumPy Slicing, Selection with Index, Column Creation and Deletion 69 -- 3.10 Python: Separate and Unite Columns 81 -- 3.11 Python: Sorting Data Frame 85 -- 4 Subsetting with Logical Conditions 99 -- 4.1 Logical Operators 99 -- 4.2 R: Row Selection 101 -- 5 Operations on Dates, Strings, and Missing Values 127 -- 5.1 R: Operations on Dates and Strings 129 -- 5.2 R: Handling Missing Values and Data Type Transformations 141 -- 5.3 R: Example with Dates, Strings, and Missing Values 154 -- 5.4 Pyhton: Operations on Dates and Strings 165 -- 5.5 Python: Handling Missing Values and Data Type Transformations 173 -- 5.6 Python: Examples with Dates, Strings, and Missing Values 182 -- 6 Pivoting and Wide-long Transformations 195 -- 6.1 R: Pivoting 197 -- 6.2 Python: Pivoting 202 -- 7 Groups and Operations on Groups 221 -- 7.1 R: Groups 222 -- 7.2 Python: Groups 244 -- 8 Conditions and Iterations 271 -- 8.1 R: Conditions and Iterations 272 -- 8.2 Python: Conditions and Iterations 284 -- 9 Functions and Multicolumn Operations 307 -- 9.1 R: User-defined Functions 308 -- 9.2 R: Multicolumn Operations 316 -- 9.3 Python: User-defined and Lambda Functions 330 -- 10 Join Data Frames 347 -- 10.1 Basic Concepts 348 -- 10.2 Python: Join Operations 369 -- 11 List/Dictionary Data Format 393 -- 11.1 R: List Data Format 395 -- 11.2 R: JSON Data Format and Use Cases 410 -- 11.3 Python: Dictionary Data Format 422 -- Questions 443 -- Index 447.