R Workshop: Part 1 2019-06-04

[bpbond]

Goal:

to use CO2 flux data to open a dataset in RStudio and create a basic plot

Data used: https://github.com/PNNL-PREMIS/SULI/blob/master/Rworkshop1_20190604_CO2.csv https://github.com/PNNL-PREMIS/SULI/blob/master/Rworkshop1_timeseries_HSLEcontrols.csv

RStudio

• [ ] Using RStudio
• [ ] Command line versus script
• [ ] How to comment
• [ ] Saving a script

Handling data: using tidyverse functions

• [ ] Reading in a dataset - readr::read_csv()
• [ ] summary(), head(), tibble::glimpse()

Visualizing with ggplot

• [ ] Using ggplot2 package
• [ ] ggplot basics: building a graphic layer by layer
• [ ] Creating a simple plot using _Rworkshop1_20190604CO2.csv
• [ ] Creating a timeseries using _Rworkshop1_timeseriesHSLEcontrols.csv

Handouts used: https://www.rstudio.com/resources/cheatsheets/

• "Data Visualization with ggplot2"
• "Data Import"

[stephpenn1]

Functions complete a task, here's how they are structured:

function_name (argument1, argument 2, ...)

Example: If you want to take the sum of 160, 47, and 10, you can use the sum() function in R

> sum(160, 47, 10) [1] 217

[bpbond]

Good meeting. We covered:

• R, RStudio, Git, GitHub - relationships
• Starting R
• Objects, variables, functions - the difference
• Data frames
• summary(), nrow(), max(), which.max(), length(),
• Indexing: vectors object[index], data frames object[row, column]
• Indexing via $ - object$column
• plot()
• Loading a package via library()
• The most popular R package: ggplot2 and its qplot() function
• qplot(x, y, data=some_object, color=column1, size=column2) + facet_wrap(~column3)
• Finished by looking at the idea of Rmarkdown document

Here's the program we wrote:

# Script to find the distance traveled by the fastest car
# B,H,L,M 2019-06-04

car_speeds <- cars$speed

print("The length of the speed vector is:")
print(length(car_speeds))
print(summary(car_speeds))

# Compute position of max speed
max_speed_pos <- which.max(car_speeds)
print("The index of the maximum speed value is:")
print(max_speed_pos)

print("The corresponding distance is:")
print(cars$dist[max_speed_pos])