Hi priya53, I'd ask this kind of question with a minimal reprex. (FAQ: What's a reproducible example (`reprex`) and how do I do one?)
For the "find out how many people" question, check out dplyr's group_by
+ tally
function. https://dplyr.tidyverse.org/reference/tally.html
For example,
# tally() is short-hand for summarise()
mtcars %>% tally()
#> n
#> 1 32
mtcars %>% group_by(cyl) %>% tally()
#> # A tibble: 3 x 2
#> cyl n
#> <dbl> <int>
#> 1 4 11
#> 2 6 7
#> 3 8 14
# count() is a short-hand for group_by() + tally()
mtcars %>% group_by(cyl) %>% tally()
gives you how many observations mtcars
has for each unique value of cyl
.