You can use the following methods to add a line to a scatter plot in seaborn:
Method 1: Add Horizontal Line
#add horizontal line at y=15 plt.axhline(y=15)
Method 2: Add Vertical Line
#add vertical line at x=4 plt.axvline(x=4)
Method 3: Add Custom Line
#add straight line that extends from (x,y) coordinates (2,0) to (6, 25) plt.plot([2, 6], [0, 25])
The following examples show how to use each method in practice.
Example 1: Add Horizontal Line to Seaborn Scatter Plot
The following code shows how to create a scatter plot in seaborn and add a horizontal line at y = 15:
import seaborn as sns
import matplotlib.pyplot as plt
#create DataFrame
df = pd.DataFrame({'x': [1, 2, 3, 4, 5, 6, 7, 8],
'y': [18, 22, 19, 14, 14, 11, 20, 28]})
#create scatterplot
sns.scatterplot(x=df.x, y=df.y)
#add horizontal line to scatterplot
plt.axhline(y=15)
Example 2: Add Vertical Line to Seaborn Scatter Plot
The following code shows how to create a scatter plot in seaborn and add a vertical line at x = 4:
import seaborn as sns
import matplotlib.pyplot as plt
#create DataFrame
df = pd.DataFrame({'x': [1, 2, 3, 4, 5, 6, 7, 8],
'y': [18, 22, 19, 14, 14, 11, 20, 28]})
#create scatterplot
sns.scatterplot(x=df.x, y=df.y)
#add vertical line to scatterplot
plt.axvline(x=4)
Example 3: Add Custom Line to Seaborn Scatter Plot
The following code shows how to create a scatter plot in seaborn and add a straight line that extends from (x,y) coordinates (2,0) to (6, 25)
import seaborn as sns
import matplotlib.pyplot as plt
#create DataFrame
df = pd.DataFrame({'x': [1, 2, 3, 4, 5, 6, 7, 8],
'y': [18, 22, 19, 14, 14, 11, 20, 28]})
#create scatterplot
sns.scatterplot(x=df.x, y=df.y)
#add custom line to scatterplot
plt.plot([2, 6], [0, 25])
Note: You can find the complete documentation to the seaborn scatter() function here.
Additional Resources
The following tutorials explain how to perform other common tasks using seaborn:
How to Add a Title to Seaborn Plots
How to Change Font Size in Seaborn Plots
How to Adjust Number of Ticks in Seaborn Plots
