# About Jesse John

Jesse is passionate about data analysis and visualization. He uses the R statistical programming language for all aspects of his work.

## Articles by Jesse John

### R Howtos

- How to Check for Missing Values Using a Boolean Operator in R
- How to Locate R Script and Data Files Without Changing the Working Directory
- How to Size Plots in Beamer Slides Made Using R Markdown
- How to Identify R Object Properties
- How to Create a Ggplot2 Visualization With a Transparent Background
- How to Include a Local Image File in an R Presentation
- How to Use the Predict Function on a Linear Regression Model in R
- $ Operator Is Invalid for Atomic Vectors Error in R
- How to Create a Random Matrix With Constant Row Sums in R
- How to Restart R in RStudio
- How to Filter a Data Frame With Multiple Conditions in R
- How to Paste Strings Without Spaces in R
- How to Use the %*% Operator in R
- How to Create a 3D Surface Plot From (x,y,z) Coordinates
- How to Create a 3D Perspective Plot in R
- How to Test Hypothesis in R
- How to Create Combinations and Permutations of Vectors in R
- How to Use Cross-Validation for a KNN Classification Model in R
- How to Create and Interpret Dummy Variables in R
- How to Test for Normality of Data in R
- How to Create and Visualize a Correlation Matrix in R
- How to Perform Time Series Analysis and Forecasts in R
- How to Perform K-Means Clustering in Base R
- How to Use the group_by Function in R Dplyr
- How to Compute Binomial Coefficients in Java
- How to Use the if and if...else Statements in R
- How to Customize the PCA Biplot in R
- How to Use the Source Function to Run Another R Script
- How to Interpret Output of system.time Function in R
- How to Convert Multiple Columns From Integer to Numeric Type in R
- How to Generate a Regular Sequence of Numbers in R
- How to Set Location of Current File as Working Directory in R Studio
- How to Add a Calculated Column to a Matrix in R
- How to Remove Object Names and Dimnames in R
- How to Find the Null Space of a Matrix in R
- How to Uninstall R and All Its Packages on Windows
- How to Remove User-Defined Objects From the Workspace in R
- Color-Blind Accessible Colors in Base R
- How to Pass Command Line Arguments to R CMD BATCH and Rscript
- How to Read a Text File Line by Line in R
- How to Use Vectorized if Function With Multiple Conditions in R
- How to Sum Selected Columns of an R Data Frame
- How to Install R Packages From Source
- How to Break a for Loop in R
- How to Drop Multiple Columns From a Data Frame Using Dplyr
- How to Stop Running R Code With the Keyboard or Mouse
- How to Export a Data Frame From R to Microsoft Excel
- How to Calculate the R-Squared Statistic in R
- How to Remove the First Character From a String in R