Add Extra Data to the Same Graph

What do you want to investigate?

If you want to compare two different sets of data, for example 2020 vs 2017, you could put two lines next to each other on your graph.

This involves lots of copy-and-pasting of your code, so can get confusing very fast! Be patient and look at your code carefully to make sure you find the correct parts.

Which parts of the code create the graph?

The first step is identifying which bits of your code will need repeating - which parts look at the data and create the graph?

year = "2020.txt"
stars = "all"
location = "all"
data.globeData(year, stars, location)
averages = []
for month in data.list:
  averages.append(sum(month)/len(month))
print(averages)
plt.plot(months, averages, color="red")

Your code will look something like the example above.

• You choose your variables.
• You access the data.
• You make a list to fill with the averages of this chosen data - this is what you are plotting on your graph.
• You print the averages (we don't actually need this line any more, so you could delete it!)
• Lastly, you plot this line on your graph, in the colour red.

All of this information is important, so copy all of these lines, and past them underneath - above any other code you have added at the end of your program!

Editing your pasted code

Now you can decide what you want your second line to show, and make a few changes to the second set of code.

• Change your variables, e.g. which year you want to look at.
• Change the name of the averages list - we don't want the program to rewrite the averages data from before, because we still want that on the graph as well! - call it e.g. averages2.
• Inside your for loop, change averages to averages2.
• Change the last line, which plots the line - change averages to averages2, and change the colour.

This can be very confusing, as all of the code looks very similar. Take it slowly, keep checking for errors, and don't panic - we can help you if you get stuck!

Look at this example, choosing data from 2020 in red and 2017 in blue:

year = "2020.txt"
stars = "all"
location = "all"
data.globeData(year, stars, location)
averages = []
for month in data.list:
  averages.append(sum(month)/len(month))
plt.plot(months, averages, color="red")

year = "2017.txt"
stars = "all"
location = "all"
data.globeData(year, stars, location)
averages2017 = []
for month in data.list:
  averages2017.append(sum(month)/len(month))
plt.plot(months, averages2017, color="blue")

plt.show()

Debugging tips

• Only add one new line at once! It's really difficult to debug lots of things at the same time, so get two lines working before adding a third.
• Check that you renamed averages in all three places.
• Check that each line is a different colour, so you can tell them apart.
• Make sure plt.show() is right at the very end.