looping over all combinations in a tibble

Question

I would like to create an index based on n for each combination of LZCODE(data below) and Bereich over 4 years and then rbind those indices in order to plot them later. As the example below shows, I can do that by hand. However that process is quite tedious and would take a lot of time. Hence, I am looking for a loop solution based on that code.

a<- trail2 %>% filter(LZCODE == 31 & Bereich == 11) %>% transform(.index=100*n/n[1])

b<- trail2 %>% filter(LZCODE == 41 & Bereich == 11) %>% transform(.index=100*n/n[1])

final<- bind_rows(a,b)

Thanks fo your help.

Data:

structure(list(Jahr = c("1985", "1997", "2009", "2018", "1985", 
"2018", "1997", "1997", "2009", "2009", "2018", "1985", "1997", 
"1985", "2018", "2009", "1997", "1985", "2009", "2018", "1997", 
"2009", "2018", "1985", "1985", "1997", "1985", "1997", "1985", 
"2018", "1985", "2009", "2018", "2009", "1997", "1997", "2009", 
"2009", "2018", "2018", "1985", "2018", "1997", "2009", "2009", 
"1985", "1997", "2018", "1985", "2009"), Bereich = c(41, 41, 
41, 41, 46, 50, 46, 50, 50, 46, 46, 50, 50, 50, 50, 50, 50, 50, 
50, 50, 50, 50, 50, 42, 50, 50, 50, 50, 50, 50, 42, 50, 50, 50, 
42, 42, 42, 42, 42, 42, 42, 43, 42, 43, 42, 41, 41, 42, 42, 41
), LZCODE = c("31", "31", "31", "31", "61", "61", "61", "61", 
"61", "61", "61", "61", "31", "31", "31", "31", "52", "52", "52", 
"52", "53", "53", "53", "31", "53", "41", "41", "51", "51", "41", 
"52", "51", "51", "41", "31", "52", "52", "31", "52", "31", "51", 
"31", "51", "31", "51", "41", "41", "51", "41", "41"), n = c(346887L, 
337676L, 318685L, 306823L, 211663L, 208646L, 206245L, 205096L, 
204536L, 203806L, 198548L, 197565L, 186488L, 184819L, 182115L, 
169676L, 139706L, 138860L, 135337L, 134505L, 95389L, 94861L, 
94638L, 93322L, 92285L, 89329L, 88517L, 87410L, 86739L, 86506L, 
83848L, 83366L, 83361L, 83249L, 82756L, 81789L, 80460L, 79102L, 
78429L, 77593L, 62154L, 61167L, 59448L, 58686L, 57644L, 56588L, 
56517L, 55279L, 54327L, 53842L), Bezeichnung = c("Ackerland", 
"Ackerland", "Ackerland", "Ackerland", "Günstige Alp- und Juraweiden", 
"Normalwald", "Günstige Alp- und Juraweiden", "Normalwald", "Normalwald", 
"Günstige Alp- und Juraweiden", "Günstige Alp- und Juraweiden", 
"Normalwald", "Normalwald", "Normalwald", "Normalwald", "Normalwald", 
"Normalwald", "Normalwald", "Normalwald", "Normalwald", "Normalwald", 
"Normalwald", "Normalwald", "Naturwiesen", "Normalwald", "Normalwald", 
"Normalwald", "Normalwald", "Normalwald", "Normalwald", "Naturwiesen", 
"Normalwald", "Normalwald", "Normalwald", "Naturwiesen", "Naturwiesen", 
"Naturwiesen", "Naturwiesen", "Naturwiesen", "Naturwiesen", "Naturwiesen", 
"Heimweiden", "Naturwiesen", "Heimweiden", "Naturwiesen", "Ackerland", 
"Ackerland", "Naturwiesen", "Naturwiesen", "Ackerland"), Bezeichnung_trim = c("Ackerland", 
"Ackerland", "Ackerland", "Ackerland", "Günstige\nAlp- und\nJuraweiden", 
"Normalwald", "Günstige\nAlp- und\nJuraweiden", "Normalwald", 
"Normalwald", "Günstige\nAlp- und\nJuraweiden", "Günstige\nAlp- und\nJuraweiden", 
"Normalwald", "Normalwald", "Normalwald", "Normalwald", "Normalwald", 
"Normalwald", "Normalwald", "Normalwald", "Normalwald", "Normalwald", 
"Normalwald", "Normalwald", "Naturwiesen", "Normalwald", "Normalwald", 
"Normalwald", "Normalwald", "Normalwald", "Normalwald", "Naturwiesen", 
"Normalwald", "Normalwald", "Normalwald", "Naturwiesen", "Naturwiesen", 
"Naturwiesen", "Naturwiesen", "Naturwiesen", "Naturwiesen", "Naturwiesen", 
"Heimweiden", "Naturwiesen", "Heimweiden", "Naturwiesen", "Ackerland", 
"Ackerland", "Naturwiesen", "Naturwiesen", "Ackerland")), row.names = c(NA, 
-50L), groups = structure(list(Jahr = c("1985", "1985", "1985", 
"1985", "1997", "1997", "1997", "1997", "2009", "2009", "2009", 
"2009", "2009", "2018", "2018", "2018", "2018", "2018"), Bereich = c(41, 
42, 46, 50, 41, 42, 46, 50, 41, 42, 43, 46, 50, 41, 42, 43, 46, 
50), .rows = structure(list(c(1L, 46L), c(24L, 31L, 41L, 49L), 
    5L, c(12L, 14L, 18L, 25L, 27L, 29L), c(2L, 47L), c(35L, 36L, 
    43L), 7L, c(8L, 13L, 17L, 21L, 26L, 28L), c(3L, 50L), c(37L, 
    38L, 45L), 44L, 10L, c(9L, 16L, 19L, 22L, 32L, 34L), 4L, 
    c(39L, 40L, 48L), 42L, 11L, c(6L, 15L, 20L, 23L, 30L, 33L
    )), ptype = integer(0), class = c("vctrs_list_of", "vctrs_vctr", 
"list"))), row.names = c(NA, -18L), class = c("tbl_df", "tbl", 
"data.frame"), .drop = TRUE), class = c("grouped_df", "tbl_df", 
"tbl", "data.frame"))

Answer 1

Do you just want

trail2 %>% 
  group_by(Bereich, LZCODE) %>% 
  mutate(Jahr = as.integer(Jahr)) %>% 
  arrange(Jahr, .by_group = TRUE) %>% 
  mutate(index = 100*n/first(n))
#> # A tibble: 50 x 7
#> # Groups:   Bereich, LZCODE [14]
#>     Jahr Bereich LZCODE      n Bezeichnung Bezeichnung_trim index
#>    <int>   <dbl> <chr>   <int> <chr>       <chr>            <dbl>
#>  1  1985      41 31     346887 Ackerland   Ackerland        100  
#>  2  1997      41 31     337676 Ackerland   Ackerland         97.3
#>  3  2009      41 31     318685 Ackerland   Ackerland         91.9
#>  4  2018      41 31     306823 Ackerland   Ackerland         88.5
#>  5  1985      41 41      56588 Ackerland   Ackerland        100  
#>  6  1997      41 41      56517 Ackerland   Ackerland         99.9
#>  7  2009      41 41      53842 Ackerland   Ackerland         95.1
#>  8  1985      42 31      93322 Naturwiesen Naturwiesen      100  
#>  9  1997      42 31      82756 Naturwiesen Naturwiesen       88.7
#> 10  2009      42 31      79102 Naturwiesen Naturwiesen       84.8
#> # … with 40 more rows

Apologies if I've misunderstood the question.