8.4 Exercise 1

Time for our first exercise!

Starting from the same object geneexp:

1. Create a scatter plot that shows sample2 on the x-axis and sample1 on the y-axis.

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ggplot(data=geneexp, mapping=aes(x=sample2, y=sample1)) + 
  geom_point()

2. Change the point color to blue, and the point size to 2.

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ggplot(data=geneexp, mapping=aes(x=sample1, y=sample2)) + 
  geom_point(color="blue", size=2)

3. Change the point shape to “square cross”

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ggplot(data=geneexp, mapping=aes(x=sample1, y=sample2)) + 
  geom_point(color="blue", size=2, shape="square cross")

4. Add the title of your choice.

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ggplot(data=geneexp, mapping=aes(x=sample1, y=sample2)) + 
  geom_point(color="blue", size=2, shape="square cross") +
  ggtitle(label="my second ggplot")

5. Add a subtitle (wait: that’s new! Google check ggtitle help page and/or “ggtitle subtitle” and see if you can find out!)

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ggplot(data=geneexp, mapping=aes(x=sample1, y=sample2)) + 
  geom_point(color="blue", size=2, shape="square cross") +
  ggtitle(label="my second ggplot", subtitle="nice blue squares")

6. Save your plot as a JPEG file, in the course folder, with dimensions 600X600 pixels.

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From the interface:

Bottom-right panel -> Plots tab -> Export -> …

From the console:

# first, save in an object
mybluescatterplot <- ggplot(data=geneexp, mapping=aes(x=sample1, y=sample2)) + 
  geom_point(color="blue", size=2, shape="square cross") +
  ggtitle(label="my second ggplot", subtitle="nice blue squares")

# then save with ggsave
ggsave(filename="myblueplot.jpg", plot=mybluescatterplot, 
       device="jpeg", 
       units="px", width=600, height=600)