Also see: https://github.com/biovcnet/topic-R/blob/master/Lesson-6/lesson-06-bvcn-full.R
Bar
library(tidyverse)
head(starwars)
# A tibble: 6 × 14
name height mass hair_color skin_color eye_color birth_year sex gender
<chr> <int> <dbl> <chr> <chr> <chr> <dbl> <chr> <chr>
1 Luke Sky… 172 77 blond fair blue 19 male mascu…
2 C-3PO 167 75 <NA> gold yellow 112 none mascu…
3 R2-D2 96 32 <NA> white, bl… red 33 none mascu…
4 Darth Va… 202 136 none white yellow 41.9 male mascu…
5 Leia Org… 150 49 brown light brown 19 fema… femin…
6 Owen Lars 178 120 brown, gr… light blue 52 male mascu…
# ℹ 5 more variables: homeworld <chr>, species <chr>, films <list>,
# vehicles <list>, starships <list>
Star Wars visuals
What species are present on each planet?
Create a bar plot where the x axis equals homeworlds and the y axis show the number of different species on each planet.
Point & line
For all humans in Star Wars, what is their relationship between height and weight? and is it impacted by their planet of origin?
First what is the data I’m looking at on Tatooine
# View(starwars)
tatooine <- starwars %>%
filter(homeworld == "Tatooine") %>% # select only those from Tatooine
data.frame
How many species on Tatooine?
unique(starwars$species); length(unique(starwars$species))
[1] "Human" "Droid" "Wookiee" "Rodian"
[5] "Hutt" NA "Yoda's species" "Trandoshan"
[9] "Mon Calamari" "Ewok" "Sullustan" "Neimodian"
[13] "Gungan" "Toydarian" "Dug" "Zabrak"
[17] "Twi'lek" "Aleena" "Vulptereen" "Xexto"
[21] "Toong" "Cerean" "Nautolan" "Tholothian"
[25] "Iktotchi" "Quermian" "Kel Dor" "Chagrian"
[29] "Geonosian" "Mirialan" "Clawdite" "Besalisk"
[33] "Kaminoan" "Skakoan" "Muun" "Togruta"
[37] "Kaleesh" "Pau'an"
unique(tatooine$species); length(unique(tatooine$species))
Bar chart example
First, example of a bar chart but something isn’t right
ggplot(tatooine, aes(x = species, y = height)) +
geom_bar(stat = "identity")
What’s wrong with this?
starwars %>%
filter(homeworld == "Tatooine") %>%
group_by(species, homeworld) %>%
summarise(MEAN_height = mean(height), MEDIAN_height = median(height),
MAX_height = max(height), MIN_height = min(height),
MEAN_mass = mean(mass), MEDIAN_mass = median(mass))
`summarise()` has grouped output by 'species'. You can override using the
`.groups` argument.
# A tibble: 2 × 8
# Groups: species [2]
species homeworld MEAN_height MEDIAN_height MAX_height MIN_height MEAN_mass
<chr> <chr> <dbl> <dbl> <int> <int> <dbl>
1 Droid Tatooine 132 132 167 97 53.5
2 Human Tatooine 179. 180. 202 163 NA
# ℹ 1 more variable: MEDIAN_mass <dbl>
hist((filter(tatooine, species == "Human"))$height)
hist((filter(tatooine, species == "Droid"))$mass)
A better way to show this data is via box plot! Let’s address that question now, but with a better graphical representation
ggplot(tatooine, aes(x = species, y = height)) +
geom_boxplot()
Boxplots in ggplot:
- median at middle
- upper/lower hinges = 1st and 3rd quartiles (25th and 75th percentiles)
- whiskers = largest/lowest value, but maxes at 1.5 * inter-quartile range (distance from upper/lower hinges)
- Outliers are shown as points
- NOTE: varies from base R ‘boxplot()’
ggplot(tatooine, aes(x = species, y = height)) +
geom_boxplot() +
geom_point()
