poorly_ordered is a vector of file names of images of patient samples from different days.
poorly_ordered
#> [1] "patient102-day9.png" "patient98-day10.png" "patient101-day10.png"
#> [4] "patient99-day11.png" "patient100-day9.png" "patient103-day10.png"
#> [7] "patient98-day11.png" "patient99-day10.png" "patient102-day11.png"
#> [10] "patient98-day9.png" "patient99-day9.png" "patient102-day10.png"
#> [13] "patient103-day11.png" "patient101-day11.png" "patient101-day9.png"
#> [16] "patient103-day9.png" "patient100-day11.png" "patient100-day10.png"How do we get this vector into order? Well, alphabetical order doesn’t work:
sort(poorly_ordered)
#> [1] "patient100-day10.png" "patient100-day11.png" "patient100-day9.png"
#> [4] "patient101-day10.png" "patient101-day11.png" "patient101-day9.png"
#> [7] "patient102-day10.png" "patient102-day11.png" "patient102-day9.png"
#> [10] "patient103-day10.png" "patient103-day11.png" "patient103-day9.png"
#> [13] "patient98-day10.png" "patient98-day11.png" "patient98-day9.png"
#> [16] "patient99-day10.png" "patient99-day11.png" "patient99-day9.png"Patient 100 comes before patient 99. This is because 1 comes before 9 in alphabetical order.
It’s possible to alphorder the numbers by prefixing them with zeroes:
strex::str_alphord_nums(poorly_ordered)
#> [1] "patient102-day09.png" "patient098-day10.png" "patient101-day10.png"
#> [4] "patient099-day11.png" "patient100-day09.png" "patient103-day10.png"
#> [7] "patient098-day11.png" "patient099-day10.png" "patient102-day11.png"
#> [10] "patient098-day09.png" "patient099-day09.png" "patient102-day10.png"
#> [13] "patient103-day11.png" "patient101-day11.png" "patient101-day09.png"
#> [16] "patient103-day09.png" "patient100-day11.png" "patient100-day10.png"Having done this, the alphabetical order is the one we want:
sort(strex::str_alphord_nums(poorly_ordered))
#> [1] "patient098-day09.png" "patient098-day10.png" "patient098-day11.png"
#> [4] "patient099-day09.png" "patient099-day10.png" "patient099-day11.png"
#> [7] "patient100-day09.png" "patient100-day10.png" "patient100-day11.png"
#> [10] "patient101-day09.png" "patient101-day10.png" "patient101-day11.png"
#> [13] "patient102-day09.png" "patient102-day10.png" "patient102-day11.png"
#> [16] "patient103-day09.png" "patient103-day10.png" "patient103-day11.png"