medium Data Visualisation

Multi-Series Line Graph

The Brief

A regional manager wants to compare daily revenue trends for three products on the same chart. Build a multi-series line graph with one line per product, a legend identifying each line, gridlines for readability, and proper axis labels. Save the chart as a PNG.

Acceptance Criteria

Tap a criterion to mark it off as you work. Tap a category header to expand or collapse.

2 Pivot or filter the data so each product has its own series of daily revenues

9 Print a confirmation message

1 Set the matplotlib backend to Agg before importing pyplot

3 Plot one line per product on the same axes using plt.plot called multiple times or a pivot plot

4 Each line must have a label so the legend works

5 Add a legend using plt.legend

6 Add gridlines using plt.grid(True) to make the chart readable

7 Add a title and axis labels

8 Save the chart as multi_line_chart.png

💡 Hints 0 / 3

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solution.py

Python 3

import matplotlib
matplotlib.use("Agg")
import matplotlib.pyplot as plt
import pandas as pd
import io

data = """Date,Product,Revenue
2024-01-01,Widget A,240
2024-01-01,Widget B,180
2024-01-01,Widget C,90
2024-01-02,Widget A,300
2024-01-02,Widget B,220
2024-01-02,Widget C,110
2024-01-03,Widget A,280
2024-01-03,Widget B,250
2024-01-03,Widget C,75
2024-01-04,Widget A,320
2024-01-04,Widget B,210
2024-01-04,Widget C,130"""

df = pd.read_csv(io.StringIO(data))

# Pivot or filter to get a series per product
# Plot all three on the same chart with a legend
# Save as multi_line_chart.png

Console