Introduction to R

Programming Basics in R

Concepts

Data frame: A collection of columns containing data, similar to a spreadsheet or SQL table.

Data structure: A format for organizing and storing data.

Argument: Information needed by a function in R in order to run.

Variable: A representation of a value in R that can be stored for later use.

Vector: A group of data elements of the same type stored in a one-dimensional sequence in R.

Factor: An object that stores categorical data where the data values are limited and usually based on a finite group, such as country or year.

Function: A body of reusable code for performing specific tasks in R.

Nested: Code that performs a particular function and is contained within code that performs a broader function.

Nested function: A function that is completely contained within another function.

List: A vector whose elements can be of any type.

Matrix: A two-dimensional collection of elements with rows and columns.

Operators

Assignment operator: An operator used to assign values to variables and vectors.

Arithmetic operator: An operator used to perform basic math operations such as addition, subtraction, multiplication, and division.

+ - * /

Relational operator: An operator used to compare values, also known as a comparator.

Logical operator: An operator that returns a logical data type.

& and | or ! not

Conditional statement: A declaration that if a certain condition holds, then a certain event must take place.

If/Else if condition:

if (condition){
    operation_1
} else if (condition) {
    operation_2
} else {
    operation_3
}

Pipe: A tool in R for expressing a sequence of multiple operations, represented with %>%.

Packages in R

CRAN(Comprehensive R Archive Network): An online archive with R packages, source, code, manuals, and documentation.

Package: A unit of reproducible R code.

Library: A directory containing all of a data analyst’s installed packages.

Vignette: Documentation for an R package that describes the problem the package is designed to solve, explains how its function can be used, and lists any dependencies on other packages.

Tidyverse: A system of packages in R with a common design philosophy of data manipulation, exploration, and visualization.

readr: An R package in Tidyverse used for importing data.

tidyr: An R package in Tidyverse used for data cleaning to make tidy data.

dplyr: An R package in Tidyverse that offers a consistent set of functions to complete common data-manipulation tasks.

ggplot2: An R package in Tidyverse that creates a variety of data visualizations by applying different visual properties to the data variables in R.