How to Change the Position of a Legend in Matplotlib
Are you tired of having legends in your Matplotlib plot always in the same location? Do you want to customize your plot’s appearance by moving the legend around?
In this article, we’ll explore different ways to change the position of a legend in Matplotlib. When visualizing data in Matplotlib, we usually add a legend to help identify the different elements of the plot. By default, the legend is placed in the “best” location to avoid overlapping with the data points.
However, in some cases, we may want to change the legend’s position to better suit our needs. In the following sections, we’ll explore different ways of doing this.
1. Default Legend Location
The easiest way to add a legend to a plot is to let Matplotlib place it in the “best” location. This means that the legend will be placed in the location that interferes the least with the data points.
However, this location may not always be optimal for our needs.
2. Specifying Legend Locations
To change the location of a legend, we can use the “loc” parameter when creating the legend. The “loc” parameter takes a string value that specifies the location of the legend.
For example, “upper left”, “top right”, “lower right”, etc. Here is an example code for creating a line plot and placing the legend in the upper left corner:
import matplotlib.pyplot as plt
x = [1, 2, 3, 4]
y = [1, 4, 9, 16]
plt.plot(x, y, label="Square")
plt.legend(loc="upper left")
plt.show()
The “loc” parameter can take other values besides the ones mentioned above.
For more information about the available options, check the Matplotlib documentation.
3. Placing Legend Outside the Plot
Sometimes, we may want to place the legend outside the plot area. For this, we can use the “bbox_to_anchor” parameter of the “legend” function.
The “bbox_to_anchor” parameter takes a tuple of two or four values that specify the location of the legend relative to the plot area. For example, to place the legend in the bottom-right corner outside the plot area, we can use the following code:
import matplotlib.pyplot as plt
x = [1, 2, 3, 4]
y = [1, 4, 9, 16]
plt.plot(x, y, label="Square")
plt.legend(bbox_to_anchor=(1.05, 1))
plt.show()
The first value of the tuple specifies the horizontal location of the legend relative to the plot area, while the second value specifies the vertical location.
In the above example, we use a value of 1.05 for the horizontal location to move the legend to the right of the plot area. The value of 1 for the vertical location places the legend at the top of the plot area.
4. Examples of Legend Placement
4.1. Upper Left Corner
Let’s see some examples of how we can use the “loc” and “bbox_to_anchor” parameters to change the position of the legend. In the first example, we’ll place the legend in the upper left corner of the plot:
import matplotlib.pyplot as plt
x = [1, 2, 3, 4]
y = [1, 4, 9, 16]
plt.plot(x, y, label="Square")
plt.legend(loc="upper left")
plt.show()
4.2. Top Right Corner
In the second example, we’ll place the legend in the top-right corner of the plot:
import matplotlib.pyplot as plt
x = [1, 2, 3, 4]
y = [1, 4, 9, 16]
plt.plot(x, y, label="Square")
plt.legend(loc="upper right")
plt.show()
Note that the “top right” value used in the “loc” parameter is incorrect. This is because “top right” is not a valid option for the “loc” parameter. Instead, we can use “upper right” to place the legend in the top-right corner.
4.3. Bottom Right Corner
In the third example, we’ll move the legend to the bottom-right corner of the plot area:
import matplotlib.pyplot as plt
x = [1, 2, 3, 4]
y = [1, 4, 9, 16]
plt.plot(x, y, label="Square")
plt.legend(bbox_to_anchor=(1.05, 0))
plt.show()
The value of 1.05 used in the “bbox_to_anchor” parameter pushes the legend outside the plot area to the right, while the value of 0 places it at the bottom of the plot area.
5. Conclusion
In this article, we explored different ways to change the position of a legend in Matplotlib. We learned how to use the “loc” and “bbox_to_anchor” parameters to customize the location of the legend.
By changing the position of the legend, we can create more readable and aesthetic plots that better convey our data.
In conclusion, this article explored different ways to change the position of a legend in Matplotlib. We learned about the default legend location and how to specify custom locations using the “loc” parameter. Additionally, we explored how to place the legend outside the plot area using the “bbox_to_anchor” parameter.
By changing the position of the legend, we can create more readable and aesthetic plots that better convey our data. One takeaway is that customizing the legend position can improve the visual appeal and clarity of our plots.