Plot a Line Graph for Pandas Dataframe with Matplotlib?

We will plot a line graph for Pandas DataFrame using the plot() method. Line graphs are excellent for visualizing trends and relationships between numerical data over time or other continuous variables.

Basic Setup

First, import the required libraries ?

import pandas as pd
import matplotlib.pyplot as plt

Creating the DataFrame

Let's create a DataFrame with car data to demonstrate line plotting ?

import pandas as pd
import matplotlib.pyplot as plt

# Create a DataFrame with car sales data
dataFrame = pd.DataFrame({
    "Car": ['BMW', 'Lexus', 'Audi', 'Mustang', 'Bentley', 'Jaguar'],
    "Reg_Price": [2000, 2500, 2800, 3000, 3200, 3500],
    "Units": [100, 120, 150, 170, 180, 200]
})

print(dataFrame)

      Car  Reg_Price  Units
0     BMW       2000    100
1   Lexus       2500    120
2    Audi       2800    150
3  Mustang       3000    170
4  Bentley       3200    180
5   Jaguar       3500    200

Plotting the Line Graph

Use plt.plot() to create a line graph showing the relationship between price and units sold ?

import pandas as pd
import matplotlib.pyplot as plt

# Create the DataFrame
dataFrame = pd.DataFrame({
    "Car": ['BMW', 'Lexus', 'Audi', 'Mustang', 'Bentley', 'Jaguar'],
    "Reg_Price": [2000, 2500, 2800, 3000, 3200, 3500],
    "Units": [100, 120, 150, 170, 180, 200]
})

# Plot line graph
plt.plot(dataFrame["Reg_Price"], dataFrame["Units"], marker='o')
plt.xlabel('Registration Price')
plt.ylabel('Units Sold')
plt.title('Car Sales: Price vs Units')
plt.grid(True)
plt.show()

Alternative Method Using DataFrame.plot()

You can also use the DataFrame's built-in plot() method for more convenience ?

import pandas as pd
import matplotlib.pyplot as plt

# Create the DataFrame
dataFrame = pd.DataFrame({
    "Car": ['BMW', 'Lexus', 'Audi', 'Mustang', 'Bentley', 'Jaguar'],
    "Reg_Price": [2000, 2500, 2800, 3000, 3200, 3500],
    "Units": [100, 120, 150, 170, 180, 200]
})

# Using DataFrame.plot() method
dataFrame.plot(x='Reg_Price', y='Units', kind='line', marker='o', 
               title='Car Sales Analysis', grid=True)
plt.xlabel('Registration Price')
plt.ylabel('Units Sold')
plt.show()

Multiple Lines on Same Graph

You can plot multiple columns as separate lines for comparison ?

import pandas as pd
import matplotlib.pyplot as plt

# Create DataFrame with additional data
dataFrame = pd.DataFrame({
    "Month": [1, 2, 3, 4, 5, 6],
    "BMW_Sales": [100, 120, 110, 130, 140, 160],
    "Audi_Sales": [90, 100, 115, 125, 135, 150]
})

# Plot multiple lines
plt.plot(dataFrame["Month"], dataFrame["BMW_Sales"], marker='o', label='BMW')
plt.plot(dataFrame["Month"], dataFrame["Audi_Sales"], marker='s', label='Audi')
plt.xlabel('Month')
plt.ylabel('Sales')
plt.title('Monthly Car Sales Comparison')
plt.legend()
plt.grid(True)
plt.show()

Key Parameters

Conclusion

Use plt.plot() for basic line graphs or DataFrame.plot() for integrated pandas plotting. Add markers, labels, and grid for better visualization and data interpretation.