---
title: bovender's personal cheat sheet
description: >
  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.
date: 2024-11-05T08:00:00+0100
draft: false
---
{{< git-info >}}
{{< param "description" >}}

## R

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

```r
# 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:

``` r
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"))
```

<sup>Created on 2024-11-05 with [reprex v2.1.1](https://reprex.tidyverse.org)</sup>

### 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.

``` r
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
```

<sup>Created on 2024-11-05 with [reprex v2.1.1](https://reprex.tidyverse.org)</sup>