ggplot2's barplot doesn't take all values into account

Question

I need ggplot2 to plot a sum of all values at specific X. What it does it just takes one value.

Excerpt of my data df:

         Day S   V
1 2016-12-27 K  60
2 2016-12-27 K 600
3 2016-12-27 M  80
4 2016-12-27 M 695

Full data's str(df):

'data.frame':   52 obs. of  3 variables:
 $ Day : POSIXlt, format: "2016-12-15" "2016-12-15" "2016-12-15" ...
 $ S   : chr  "K" "K" "M" "M" ...
 $ V   : num  50 560 255 460 110 500 145 460 40 630 ...

I use following code to make a graph, but for some reason only values 600 and 695 are displayed. I would like it to display 660 and 775.

ggplot(data = daneDzien, aes(x = Day, y = V, fill = S)) + 
  geom_bar(stat = "identity", position = "dodge", color = "black")

I'm pretty sure it worked well for me in the past, but today I'm out of ideas what to do to make it work.

Answer 1

One option is to summarize the dataset outside of ggplot2, so you have one value per "S" level per date.

To work within ggplot2 instead you could summarize via stat = "summary" with fun.y = sum.

ggplot(df, aes(x = Day, y = V, fill = S)) +
    geom_bar(stat = "summary", fun.y = sum, position = "dodge", color = "black")