Making a bar graph with ggplot and Shiny in R

Question

I'm trying to make a bar graph with ggplot and Shiny in R, but my data is structured in a weird way that seems to make this task more difficult than expected. The dataframe looks something like this:

Name       Percent 1     Percent 2    Percent 3
A          45            10           45
B          30            20           50
C          10            35           55

Basically, I'd want to make my bar graph to show each percent as a "bar" based on what someone selects. For example, if my Shiny app has a dropdown menu that says "select name" and someone picks A, the resulting graphic should be three bars that show 45%, 10%, and 45%, with "Percent 1", "Percent 2", and "Percent 3" as the labels.

Thanks for any help!

Answer 1

You first need to make sure that you have "tidy data" (= every variable goes in a column, and every column is a variable). In order to do that you can use the gather() function of the tidyr package; e.g.:

gather(stack, percent, value, -Name)

You can find out more information about tidy data here: https://r4ds.had.co.nz/tidy-data.html

Answer 2

I think you have to do some data tidying before you can do any visualization with this data. Here are some code sample that could do this job for you:

stack <- data.frame( name = c('A','B','C'),
                      percent1 = c(45,10,45),
                      percent2 = c(30,20,50),
                      percent3 = c(10,35,55),
                      stringsAsFactors = FALSE)
stack_ <- stack %>% gather(percent, value, percent1:percent3)

stack_ <- stack_ %>% filter(name == 'A')

p<-ggplot(data=stack_, aes(x=percent, y=value)) +
  geom_bar(stat="identity")
p