Python Data Visualization Transcripts
Chapter: Plotly
Lecture: Line bar area

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0:00 Now we're gonna look at some additional plot types and I'm going to create a new
0:08 data frame that has the average fuel economy and the number of cars by year.
0:14 And this will be a simple data frame that we'll use for plotting a line chart and some other plot types. So to walk through this I am grouping by I'm
0:24 taking my data frame, grouping it by year in class. I don't want it to have a separate hierarchical index.
0:32 That's why I set this to false and I'm aggregating our fuel cost to get them average and the vehicle to get the total number.
0:40 This is why I added the vehicle column to our data frame so that we can count the number of vehicles per year.
0:45 I'm rounding it to make it a little bit easier and this is our data frame So you can see for each year I can see the cars and what the
0:53 average fuel cost was and how many fit into that. So now that we have this data, let's create a line chart to show what that averages over time.
1:04 So now this is an interesting chart. We can look at the wagons over time and see how the fuel cost decreases and
1:14 then we can do that for each of these other groups. So let me walk through what the line does. So I use my average by year.
1:19 Class data frame, the X axis is the year. The wise the fuel cost. I'm telling it to group the lines together by class
1:29 summary because if you see this data, we have multiple different entries per year.
1:36 So it groups it by class summary which makes this really easy to show all these
1:42 together and then we have our similar hover effects that we have seen earlier. So that's a good example for the line chart.
1:51 And what's interesting what I like about plotly express that I can change it instead of just doing a line chart.
1:56 Maybe I want to do an area chart and let's see what that looks like. So now the same basic code except I just changed it to PX.area shows
2:05 an area chart so we can kind of see what that looks like over time. And then if you want to see a good old bar chart, change it to show a bar chart.
2:16 So now I can see for each year by each class how that the number of vehicles per year. So in this case I said that the X.
2:25 Is the year and then Y is vehicle.
2:28 So if we just want to see how many vehicles there are per year in each class then it is very easy to see in this bar chart.

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