matplotlib legend location manual with code examples

Matplotlib is a powerful data visualization library in Python that allows users to create a wide variety of plots and charts. One of the most important elements of a plot is the legend, which is used to label the different data sets or elements in the plot. In this article, we will discuss how to manually set the location of the legend in a Matplotlib plot using code examples.

First, let's start with a simple example of creating a line plot using Matplotlib. In this example, we will create a plot with two lines, each with a different color. We will then add a legend to the plot to label the two lines. By default, the legend will be located in the upper right corner of the plot.

import matplotlib.pyplot as plt

# Create some data
x = [1, 2, 3, 4, 5]
y1 = [1, 2, 3, 4, 5]
y2 = [5, 4, 3, 2, 1]

# Create the plot
fig, ax = plt.subplots()
ax.plot(x, y1, '-', color='red', label='Line 1')
ax.plot(x, y2, '-', color='blue', label='Line 2')

# Add a legend
ax.legend()

# Show the plot
plt.show()

The above code will produce a plot with a legend located in the upper right corner of the plot. However, there may be cases where you want to place the legend in a different location on the plot. In order to do this, you can use the loc parameter of the legend() function. The loc parameter takes an integer value that corresponds to a specific location on the plot.

Here is an example of how to place the legend in the lower right corner of the plot:

import matplotlib.pyplot as plt

# Create some data
x = [1, 2, 3, 4, 5]
y1 = [1, 2, 3, 4, 5]
y2 = [5, 4, 3, 2, 1]

# Create the plot
fig, ax = plt.subplots()
ax.plot(x, y1, '-', color='red', label='Line 1')
ax.plot(x, y2, '-', color='blue', label='Line 2')

# Add a legend
ax.legend(loc=4)

# Show the plot
plt.show()

The above code will produce a plot with a legend located in the lower right corner of the plot. The loc parameter takes an integer value between 0 and 10, each corresponding to a different location on the plot. Here are some examples of the loc parameter values and their corresponding locations:

• loc=0: best location (upper left by default)
• loc=1: upper right
• loc=2: upper left
• loc=3: lower left
• loc=4: lower right
• loc=5: right
• loc=6: center left
• loc=7: center right
• loc=8: lower center
• loc=9: upper center
• loc=10: center

Alternatively, you can use string values such as 'upper left', 'upper right', '
Another way to set the location of the legend in Matplotlib is by using the bbox_to_anchor parameter. The bbox_to_anchor parameter allows you to specify the coordinates of the legend in terms of the bounding box of the axes. For example, you can use the bbox_to_anchor parameter to place the legend at a specific point on the plot, regardless of the size of the plot.

Here is an example of how to use the bbox_to_anchor parameter to place the legend at the point (1,0) on the plot:

import matplotlib.pyplot as plt

# Create some data
x = [1, 2, 3, 4, 5]
y1 = [1, 2, 3, 4, 5]
y2 = [5, 4, 3, 2, 1]

# Create the plot
fig, ax = plt.subplots()
ax.plot(x, y1, '-', color='red', label='Line 1')
ax.plot(x, y2, '-', color='blue', label='Line 2')

# Add a legend
ax.legend(bbox_to_anchor=(1, 0))

# Show the plot
plt.show()

Another useful parameter when working with legends in Matplotlib is ncol. The ncol parameter allows you to specify the number of columns in the legend. This can be useful when you have a large number of items in the legend and want to organize them into multiple columns.

Here is an example of how to use the ncol parameter to create a legend with two columns:

import matplotlib.pyplot as plt

# Create some data
x = [1, 2, 3, 4, 5]
y1 = [1, 2, 3, 4, 5]
y2 = [5, 4, 3, 2, 1]
y3 = [1,4,9,16,25]
y4 = [2,8,18,32,50]
# Create the plot
fig, ax = plt.subplots()
ax.plot(x, y1, '-', color='red', label='Line 1')
ax.plot(x, y2, '-', color='blue', label='Line 2')
ax.plot(x, y3, '-', color='green', label='Line 3')
ax.plot(x, y4, '-', color='black', label='Line 4')

# Add a legend
ax.legend(ncol=2)

# Show the plot
plt.show()

In addition to the above parameters, you can also use other techniques like using legend(prop={'size': 6}) to set the font size of the legend or legend(title='My Title') to add a title to the legend.

In conclusion, Matplotlib provides several ways to control the location of the legend in a plot. By using the loc parameter, the bbox_to_anchor parameter and ncol parameter, you can easily place the legend in the desired location on the plot and make it more organized.

Popular questions

1. What is the default location of the legend in a Matplotlib plot?
   Answer: The default location of the legend in a Matplotlib plot is in the upper right corner.

2. How can you manually set the location of the legend in a Matplotlib plot?
   Answer: You can manually set the location of the legend in a Matplotlib plot by using the loc parameter of the legend() function. The loc parameter takes an integer value between 0 and 10, each corresponding to a different location on the plot.

3. What is the bbox_to_anchor parameter in Matplotlib and how is it used?
   Answer: The bbox_to_anchor parameter in Matplotlib allows you to specify the coordinates of the legend in terms of the bounding box of the axes. It can be used to place the legend at a specific point on the plot, regardless of the size of the plot.

4. What is the ncol parameter in Matplotlib and how is it used?
   Answer: The ncol parameter in Matplotlib allows you to specify the number of columns in the legend. It can be used when you have a large number of items in the legend and want to organize them into multiple columns.

5. What other techniques can be used to customize the legend in a Matplotlib plot?
   Answer: Other techniques that can be used to customize the legend in a Matplotlib plot include using legend(prop={'size': 6}) to set the font size of the legend or legend(title='My Title') to add a title to the legend.

Tag

Matplotlib