As a teacher, I not only teach but also assess the achievements of students. One example of a typical student assignments is a presentation. You know, powerpoint slides and stuff.
For that purpose, I often need to map students to one of several time slots. Here’s the R code I use for that purpose.
library(tidyverse)## ── Attaching packages ────────────────────────────────────────────────────────────────────────────────────────────────────────────────── tidyverse 1.2.1 ──## ✔ ggplot2 3.0.0 ✔ purrr 0.2.5
## ✔ tibble 1.4.2 ✔ dplyr 0.7.6
## ✔ tidyr 0.8.1 ✔ stringr 1.3.1
## ✔ readr 1.1.1 ✔ forcats 0.3.0## Warning: package 'dplyr' was built under R version 3.5.1## ── Conflicts ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────── tidyverse_conflicts() ──
## ✖ dplyr::filter() masks stats::filter()
## ✖ dplyr::lag() masks stats::lag()How many students are subscribed to the assignment?
stud_count <- 20Let’s say there 20 students in the course.
Let’s assume, for each time slot, 10 students can be allocated (not more time for more student for one slot).
slots_count <- (stud_count / 10) %>% ceiling # round to next integer
slots_count## [1] 2That gives 2 time slots.
Now let’s map the students to the slots on a random base:
slot <- 1:max(slots_count)
set.seed(2018)
allocation <- replicate(n = 10,
sample(x = slot)) %>% as.vectorWhat we’ve done here is:
- Take the first triplet of students and randomly assign them to the three slots (so that each of the three students has a unique slot, ie sampling without replacement)
- Repeat that for the rest of the triplets
Let’s check whether the allocation has worked:
table(allocation)## allocation
## 1 2
## 10 10Worked out. Presentations ahead.
Let’s save the vector as a csv-file for the easy of interfacing with other applications such as Excel.
library(rio)
export(data_frame(slots = allocation),
file = "slots.csv")