R to Latex summary table for categorical variables by year

year <- c(2000,2000,2000,2001,2001,2001)
gender <- c("F","M","M","F","F","M")
grade <- c("A","B","C","C","B","A")
df <- data.frame(year,gender,grade)

I would like to make a summary table but minimize manual codes and automates the process as much as possible. In my project, I have 170 variables to summarise. I tried tidyverse group by but didn't get the result that I want. I will use xtable to move to latex file. (I tried add.to.row but failed to add "Gender" on the first line.)

Here is the outcome that I want.

Please help me to draw this table. I need the variable names in the table.

You can use pivot_longer and summarise to generate the summary values.

library(tidyverse)

df %>% 
  pivot_longer(-year) %>% 
  group_by(year, name, value) %>% 
  summarise(n = n()) %>% 
  mutate(prop = round(n / sum(n), 3) * 100)

# A tibble: 10 x 5
# Groups:   year, name [4]
    year name   value     n  prop
   <dbl> <chr>  <chr> <int> <dbl>
 1  2000 gender F         1  33.3
 2  2000 gender M         2  66.7
 3  2000 grade  A         1  33.3
 4  2000 grade  B         1  33.3
 5  2000 grade  C         1  33.3
 6  2001 gender F         2  66.7
 7  2001 gender M         1  33.3
 8  2001 grade  A         1  33.3
 9  2001 grade  B         1  33.3
10  2001 grade  C         1  33.3

You can also get closer to your desired table by joining values in a formatted string, and then using pivot_wider:

df %>% 
  pivot_longer(-year) %>% 
  group_by(year, name, value) %>% 
  summarise(n = n()) %>% 
  mutate(prop = round(n / sum(n), 3) * 100,
         summary_str = glue::glue("{n}({prop}%)")) %>% 
  pivot_wider(id_cols = c(name, value), names_from = "year", 
              values_from = "summary_str") 

  name   value `2000`   `2001`  
  <chr>  <chr> <glue>   <glue>  
1 gender F     1(33.3%) 2(66.7%)
2 gender M     2(66.7%) 1(33.3%)
3 grade  A     1(33.3%) 1(33.3%)
4 grade  B     1(33.3%) 1(33.3%)
5 grade  C     1(33.3%) 1(33.3%)