Setting x and y Scales

The c() function combines multiple values. I think of it as "combine" in my head (though I'm not sure that's what its developers would actually call it). In this case, it means combine 0 and 50 so that 0 is the low value and 50 is the high value. Does that help?

Thanks for pointing that out, Acarilia! We fixed it and now the code shows the right value. 😉

also how to update the x-axis and y axis title?

Hi Gaurab! I think what you're looking for is the scale_x_discrete layer. If your data is continuous and you want to display categories, you'll need to create these first (you can use mutate combined with case_when, for example, to create these categories).

To update the axis title, you can add a theme layer with element_blank for the x and/or y titles, like this:

theme(axis.title.x = element_blank())

Hi Mike! That's correct: the thing is the point of reference. The bar ends exactly at the same point, but because the numbers in the axes are different, we get the impression that the bars end at different points.

Try adding a horizontal lines at 120 and 150 to visualize that:

ggplot(data = penguins_by_species,
       mapping = aes(x = species,
                     y = n,
                     fill = species)) +
  geom_col() +
  scale_fill_viridis_d() +
  scale_y_continuous(limits = c(0, 200)) +
  # scale_y_continuous(limits = c(0, 200),
  #                    breaks = c(0, 40, 80, 120, 160)) +
  # scale_y_continuous(limits = c(0, 200),
  #                    breaks = seq(0, 200, 10)) +
  geom_hline(yintercept = c(120, 150), color = "red")

Run the code with the different scales, one at a time, and use the left and right arrows on the plot panel to navigate the plots and see the difference. [= I suggest popping out the plots panel (you can do that by clicking on the "zoom" button there) to make it bigger and easier to see the scales.

Hi,

Is there a way to attach an image to a message? Here is a Google link to my image :

Original Image: https://drive.google.com/file/d/17wVn6fGb1VNiBmDQx3cUrwKc68WE_e9H/view?usp=sharing

Image with horizontal lines at 120 and 150 : https://drive.google.com/file/d/1VXLwvAfp_vFVXR6sVEPMIFXSmTGNdI8U/view?usp=sharing

I see what you are saying about the bars, but that doesn't get around the fact that the vertical axis is not correct. This can lead to wrong conclusions. I don't understand the point of a command that will change the scale of the vertical axis without changing the data as well.

Obviously I can take out the scale_y_continuous command and the visualization is fine. I am just trying to wrap my head around the command to make it make sense.

ggplot(penguins_by_species, aes(x=species, 
                                y=n, 
                                fill=species,
                                label = n)) +
  geom_bar(stat="identity") +
  scale_fill_viridis_d() +
  scale_y_continuous(limits = c(0,200),
                     labels = c(0, 40, 80, 120, 160)) +
  geom_label(vjust=1.5, color="white") +
  geom_hline(yintercept = c(120, 150), color = "red")

Thanks, Mike

Hey Mike! Thanks for expanding on this and sending your code! I've found a "bug" on your code and it completely makes sense now!

You're using a labels argument inside the scale_y_continuous layer - this is a way for you to set whatever text you want on the breaks of the y axis. Instead, the original code uses the breaks arguments, which shows or hides specific breaks in the scale shown in the y axis. Try adding this layer to your plot to see the mess it can make, and then try commenting out the labels argument:

  scale_y_continuous(limits = c(0, 200), 
                     labels = c(0, "forty", 160, "top"),
                     breaks = c(0, 40, 120, 160)) +