blog/content/cheatsheet.md

title	description	date	draft
bovender's personal cheat sheet	On this page, I collect bits and pieces of information that I never seem to be able to memorize. This stuff is helpful for me and maybe it is helpful for you, too, internet wanderer.	2024-11-05T08:00:00+0100	false

{{< git-info >}} {{< param "description" >}}

R

Print R objects so that they can be re-generated from code

# dput takes an R object
dput(x, file = "", control = c("keepNA", "keepInteger", "niceNames", "showAttributes"))
dget(file, keep.source = FALSE)

# dump takes a list of R object names
dump(list, file = "dumpdata.R", append = FALSE, control = "all", envir = parent.frame(), evaluate = TRUE)

Example:

library(dplyr)
my_data <-
  starwars |>
  select(species, homeworld)
dput(my_data)
#> structure(list(species = c("Human", "Droid", "Droid", "Human", 
#> "Human", "Human", "Human", "Droid", "Human", "Human", "Human", 
#> "Human", "Wookiee", "Human", "Rodian", "Hutt", "Human", NA, "Yoda's species", 
#> "Human", "Human", "Droid", "Trandoshan", "Human", "Human", "Mon Calamari", 
#> "Human", "Human", "Ewok", "Sullustan", "Human", "Neimodian", 
#> "Human", "Human", "Gungan", "Gungan", "Gungan", "Human", "Toydarian", 
#> "Dug", "Human", "Human", "Zabrak", "Twi'lek", "Twi'lek", "Aleena", 
#> "Vulptereen", "Xexto", "Toong", "Human", "Cerean", "Nautolan", 
#> "Zabrak", "Tholothian", "Iktotchi", "Quermian", "Kel Dor", "Chagrian", 
#> NA, NA, "Human", "Geonosian", "Mirialan", "Mirialan", "Human", 
#> "Human", "Human", "Human", "Clawdite", "Besalisk", "Kaminoan", 
#> "Kaminoan", "Human", "Droid", "Skakoan", "Muun", "Togruta", "Kaleesh", 
#> "Wookiee", "Human", NA, "Pau'an", "Human", "Human", "Human", 
#> "Droid", "Human"), homeworld = c("Tatooine", "Tatooine", "Naboo", 
#> "Tatooine", "Alderaan", "Tatooine", "Tatooine", "Tatooine", "Tatooine", 
#> "Stewjon", "Tatooine", "Eriadu", "Kashyyyk", "Corellia", "Rodia", 
#> "Nal Hutta", "Corellia", "Bestine IV", NA, "Naboo", "Kamino", 
#> NA, "Trandosha", "Socorro", "Bespin", "Mon Cala", "Chandrila", 
#> NA, "Endor", "Sullust", NA, "Cato Neimoidia", "Coruscant", "Naboo", 
#> "Naboo", "Naboo", "Naboo", "Naboo", "Toydaria", "Malastare", 
#> "Naboo", "Tatooine", "Dathomir", "Ryloth", "Ryloth", "Aleen Minor", 
#> "Vulpter", "Troiken", "Tund", "Haruun Kal", "Cerea", "Glee Anselm", 
#> "Iridonia", "Coruscant", "Iktotch", "Quermia", "Dorin", "Champala", 
#> "Naboo", "Naboo", "Tatooine", "Geonosis", "Mirial", "Mirial", 
#> "Naboo", "Serenno", "Alderaan", "Concord Dawn", "Zolan", "Ojom", 
#> "Kamino", "Kamino", "Coruscant", NA, "Skako", "Muunilinst", "Shili", 
#> "Kalee", "Kashyyyk", "Alderaan", "Umbara", "Utapau", NA, NA, 
#> NA, NA, NA)), row.names = c(NA, -87L), class = c("tbl_df", "tbl", 
#> "data.frame"))

^{Created on 2024-11-05 with reprex v2.1.1}

Calculate percentages of subgroups

Principle: Group the dataset and summarize by counting (n()), drop the last group while doing so, then mutate the dataset by adding the count divided by the sum of counts.

Hint to better understand the example: Look at the sexes in black-eyed subjects.

library(dplyr)
starwars |>
  group_by(eye_color, gender) |>
  summarize(n = n(), .groups = "drop_last") |>
  mutate(p = n/sum(n))
#> # A tibble: 23 × 4
#> # Groups:   eye_color [15]
#>    eye_color gender        n      p
#>    <chr>     <chr>     <int>  <dbl>
#>  1 black     feminine      2 0.2   
#>  2 black     masculine     8 0.8   
#>  3 blue      feminine      6 0.316 
#>  4 blue      masculine    12 0.632 
#>  5 blue      <NA>          1 0.0526
#>  6 blue-gray masculine     1 1     
#>  7 brown     feminine      4 0.190 
#>  8 brown     masculine    15 0.714 
#>  9 brown     <NA>          2 0.0952
#> 10 dark      masculine     1 1     
#> # ℹ 13 more rows

^{Created on 2024-11-05 with reprex v2.1.1}