Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 1 Module 2 Moving Between Excel & R Worlds Do See & HearRead Learning PowerPoint must be in View Show Mode to See videos and hyperlinks

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 2 Module 2 Moving Between Excel & R Worlds What We’ll Cover Identify Essential Concepts that Excel Users need to understand to learn R Establish correspondence between R and Excel terminology Show same calculations and plots in Excel and R –Start with Excel workbook, basic calculations and simple plot –Export the Workbook to CSV file –Reproduce calculations, plots in R

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 3 Excel & R Worlds 30 Minute Video – Walks through Excel & R features Click video image to start video

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 4 Comparison of Excel & R Worlds ExcelR Display Look at DataLook at Script

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 5 Display Excel World –See data right on screen –Formulas are not visible, need to select cell to see or use Control ~

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 6 Display Excel World –See data right on screen –Formulas are not visible, need to select cell to see or use Control ~ R World –See script on screen, comparable to seeing formula view in Excel –View Data Options: Text Editor (Notepad.exe) Can view my_data data.frame with R functions: –my_data shows all data –head(my_data,n) shows first n rows –tail(my_data,n) shows last n rows

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 7 Comparison of Excel & R Worlds ExcelR Display Look at DataLook at Script User Interface Point & ClickCommand Line

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 8 User Interface Point & Click versus Command Line Excel users very familiar & comfortable with point & click To make a chart in Excel 2003, we: –Click chart icon –We follow chart wizard By answering wizard prompts, we pass chart parameters to the Excel chart engine

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 9 User Interface Point & Click versus Command Line Excel users very familiar & comfortable with point & click To make a chart in Excel 2003, we: –Click chart icon –We follow chart wizard By answering wizard prompts, we pass chart parameters to the Excel chart engine R’s approach is to have user directly specify chart parameters in function call: > plot(anom ~ yr, data = my_Data, type = “l”, col = “red”)

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 10 Comparison of Excel & R Worlds ExcelR Display Look at DataLook at Script User Interface Point & ClickCommand Line Data Structure Workbook Worksheet Column Cell Data.frame (List, Matrix, Array) Vector Vector[I]

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 11 Data Structure Everything is by address: row/col or range name Range(B2:B22) Sheet1!range(“B2:B22”) B6 Excel WorldR World Everything is an object with a name Column of data is called vector with name (default is V1) Group of vectors called data frame data$Glob or data[2] data$Glob[5] or data[5,2]

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 12 Data Structure ExcelR Data groupWorksheet dataset with * Same # rows data.frame Column of dataColumn B B2:B100 Vector Data value in rangeB3Vector[3] Dynamic Data Range Define Name =offset() Vectors dynamic

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 13 Comparison of Excel & R Worlds ExcelR Display Look at DataLook at Script User Interface Point & ClickCommand Line Data Structure Workbook Worksheet Column Cell Data.frame (List, Matrix, Array) Vector Vector[I] Data Types numeric character logical numeric character logical factor

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 14 Data Types Excel & R Have 3 similar data types Numeric (1, 11, 19.2) Character (“Joe”, “Bill”) Logical (T,F) R has Factor Data Type

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 15 Factors – What Are They? Why Are They important? Data sets often contain categorical data that subdivides data –Gender (Male, Female) –Language ( English, French, Chinese, etc) –Energy Source (fossil, renewable) Why use factor data type? 1.Data integrity – limits data to specified levels 2.Easy to summarize data by factor levels 3.Multivariate plotting – distinguish by factor Character data type does not ensure data integrity (M/F; m/f, male/female) R’s factor () function good for categorical data >gender_f <- factor(gender, levels = c(“M”, “F”) –Establishes factor gender_f –Sets acceptable values with levels argument to M or F

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 16 Comparison of Excel & R Worlds ExcelR Display Look at DataLook at Script User Interface Point & ClickCommand Line Data Structure Workbook Worksheet Column Cell Data.frame (List, Matrix, Array) Vector Vector[I] Data Types numeric character logical numeric character logical factor Data Summary & Query by Criteria sumif(); sumproduct(); {Array formulas}; Pivot Table Index (,,,Match(,,),) as.factor() subset(), tapply() which()

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 17 How to Summarize Data by Factor Menu Array formulas are not user friendly Excel WorldR World

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 18 Comparison of Excel & R Worlds ExcelR Display Look at DataLook at Script User Interface Point & ClickCommand Line Data Structure Workbook Worksheet Column Cell Data.frame (List, Matrix, Array) Vector Vector[I] Data Types numeric character logical numeric character logical factor Data Summary & Query by Criteria sumif(); sumproduct(); {Array formulas}; Pivot Table =Index(,, Match,,),) as.factor() subset(), tapply() which() Missing Values Inconsistent HandlingProper Handling

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 19 Missing Data Excel has serious shortcomings when it comes to handling missing data –Blanks can be converted to zero when blank cell is referenced in formula –Functions like regression can not handle blank cells in range R addresses missing data directly –User specifies code for missing data in read.table() –User specifies how to handle missing data in calculations Video on next slide shows how Excel & R handle missing data

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 20 Missing Data Click video image to start video

Learn R Toolkit D Kelly O'DayExcel & R WorldsMod 2 - Excel & R Worlds: 21 Comparison of Excel & R Worlds ExcelR Display Look at DataLook at Script User Interface Point & ClickCommand Line Data Structure Workbook Worksheet Column Cell Data.frame (List, Matrix, Array) Vector Vector[I] Data Types numeric character logical numeric character logical factor Data Summary by Criteria sumif(); sumproduct(); {Array formulas}; Pivot Table subset() Missing Values Inconsistent HandlingProper Handling