r-ecology_instructor-cheatsheet.md

Lesson 00 - Setup + R Intro

Start Rstudio Create Project Create a Data Directory and Rscript

Explain:

• diff btw console and script
• + sign means waiting for more input
• commenting
• variable assignment
• functions and aruments (sqrt + round)
• using ??

Rest of lesson goes over how to get help online

Lesson 01 - Intro to R

Show webpage script example

Explain:

• math with assigned variables (exercise)
• numeric and character vectors

• length, class, str of vectors
• concatentate values to vectors
• subsetting vectors (challenge)

Lesson 02 -Starting with data

Download and read csv datafile

• inspect with head() and str() (exercise)

factors are:

• categorical variables
• neccessary for many statistical operations
• ordered alphabetically be default

Explain:

• nlevels(), levels()
• try math with factors - convert to numeric (exercise)

Lesson 03 - data.frame

Create a DF:

• Imported from spreadsheet
• Manually
• (exercise)

Inspect a DF using:

• dim, nrow, ncol, head, tail, names, rownames, str, summary
• subsetting indices (explain sequences) (exercise)
• subsetting by column name

Lesson 04 - dplyr

Explain:

• installing and loading packages
• bracket subsetting can be complicated so dplyr:: filter, select
• create new columns using mutate
• calculate stats on groups using group_by

Lesson 05 - ggplot2

Use baseplotting to plot weight vs hindfoot length Use ggplot2 to plot weight vs hindfoot length

• add transparency
• add colors

Make ggplot2 boxplot of species id vs weight

• add points with geom_jitter

Make ggplot2 timeseries plot of species_id counts by year with geom_line

• seperate line (group) by species_id
• color by species_id

Create seperate plot of each species using facet_wrap

Introduce themes and labels (labs)

Lesson 06 - SQL

Recap benefits of databases

• reproducible analysis
• ability to make very large querys

• Connect to our sqlite file