Back_MN_R_Cheatsheet.knit

# Keep only 2 columns
select(porgs, id, age)
# Drop the mass column
select(porgs, -mass)
# Put the age column first, but
# keep everything else the same
select(porgs, age, everything())

# Sort by age w/ YOUNGEST on top
arrange(porgs, age)
# Sort by age w/ ELDEST on top
arrange(porgs, desc(age))
# Sort by colors and then by age
arrange(porgs, color, desc(age))

Convert text to Date

Function	Order of Input	Output
`mdy()`	Month-Day-Year :: `05-18-2019`	`2019-05-18`
`mdy_hm()`	Month-Day-Year Hour:Minutes :: `05-18-2019 8:35`	`2019-05-18` `08:35:00 UTC`
`mdy_hms()`	Month-Day-Year Hour:Mins:Secs :: `05-18-2019 8:35:22`	`2019-05-18` `08:35:22 UTC`

Date parts

Function	Date element
`year()`	Year
`month()`	Month as 1,2,3
`day()`	Day of the month
`wday()`	Day of the week
`hour()`	Hour of the day (24hr)
`tz()`	Time zone

left_join() keeps all rows and columns in the left table, and joins rows in the right table with matching IDs.

# Table w/ porg ages and heights
porgs

# Table w/ porg names
porg_names

# Join together by id columns
together <- left_join(porgs, 
                      porg_names, 
                      by = "id")

Data tables

library(readr)
# Save data to a CSV text file
write_csv(porgs, "my_porg_data.csv")

Plots and images

library(ggsave) 
# Save the last plot you made
ggsave("most_recent_plot.png")
# Save earlier plot stored to variable
best_plot <- ggplot()
ggsave(best_plot, "best_plot.png")

Online

Google: r or rstats + "question"
Stackoverflow.com + [r] tag
TEAMS Channel - Help requests!

From R

Go to: Help > Cheatsheets
Type ? in the Console

# Function help
?read_csv
# Search help
help.search("boxplot")

#rstats on
ROpenSci.org
Rweekly.org
RLadies.org
R-Bloggers.com
TidyTuesdays
useR Conferences

Run line: CTRL+ENTER
Save script: CTRL+S
Tidy code: highlight+CTRL+Shift+A

Find data

Use ifelse() to create new values that depend on the value of another column. For example, to only label the porgs with a height over 60 cm as “tall”.

# When a porg's height is > 60 cm label it as "tall", 
# otherwise label it as "short"
mutate(porgs, label = ifelse(height > 60, "tall", "short"))

Barbara.Monaco

Kristie.Ellickson

Dorian.Kvale

Carl.Stenoien

Andrea.Borich

Derek.Nagel

R

for MINNESOTA

Online training @ mn-r.netlify.app

Please remember porgs are not for dinner.