Font properties customization in Matplotlib - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of font properties in matplotlib?

Font properties control the appearance of text in plots, such as font family, size, weight, and style, to make the text clear and visually appealing.

beginner

How do you change the font size of a title in matplotlib?

Use the fontsize parameter in the title() function, for example: plt.title('My Title', fontsize=14).

beginner

What does the fontweight property control?

The fontweight property controls how thick or bold the text appears. Common values are 'normal', 'bold', and numeric weights like 700.

intermediate

How can you set multiple font properties at once in matplotlib?

You can create a dictionary with font properties like {'family': 'serif', 'size': 12, 'weight': 'bold'} and pass it using the fontdict parameter, e.g., plt.xlabel('X', fontdict=font).

intermediate

What is the difference between fontfamily and fontname in matplotlib?

fontfamily specifies a generic font category like 'serif' or 'sans-serif', while fontname specifies a specific font like 'Arial' or 'Times New Roman'.

Which parameter changes the font size of axis labels in matplotlib?

A fontstyle

B fontweight

C fontcolor

D fontsize

The fontsize parameter controls the size of the font for axis labels.

How do you make text bold in matplotlib?

A Set fontweight='bold'

B Set fontsize=20

C Set fontstyle='italic'

D Set fontfamily='serif'

The fontweight property set to 'bold' makes text bold.

What does the fontdict parameter do?

A Sets multiple font properties at once

B Changes the plot background color

C Adjusts the plot size

D Adds grid lines

fontdict lets you pass a dictionary of font properties to style text.

Which font property controls the font family category?

A fontsize

B fontfamily

C fontweight

D fontstyle

fontfamily sets the generic font category like serif or sans-serif.

If you want italic text, which property should you use?

A fontweight='italic'

B fontsize=italic

C fontstyle='italic'

D fontfamily='italic'

The fontstyle property set to 'italic' makes text italic.

Explain how to customize font properties for a plot title in matplotlib.

Think about parameters in plt.title() and how to pass a dictionary of font properties.

Describe the difference between fontfamily and fontname in matplotlib font customization.

Consider how you choose a broad font type versus a specific font face.

Practice

1. Which font property controls the thickness of the text in a matplotlib plot?

easy

A. family

B. size

C. weight

D. color

Solution

1. Step 1: Understand font properties

   Font properties include size, weight, family, style, and color.

2. Step 2: Identify the property for thickness

   The thickness or boldness of text is controlled by the 'weight' property.

3. Final Answer:

   weight -> Option C

4. Quick Check:

   Font thickness = weight [OK]

Hint: Thickness means weight in font properties [OK]

Common Mistakes:

• Confusing size with weight
• Thinking color controls thickness
• Mixing family with weight

2. Which of the following is the correct way to set the font size of a plot title to 16 using fontdict in matplotlib?

easy

A. plt.title('My Title', font={'fontsize':16})

B. plt.title('My Title', fontdict={'size':16})

C. plt.title('My Title', font={'size':16})

D. plt.title('My Title', fontdict={'fontsize':16})

Solution

1. Step 1: Recall fontdict usage

   In matplotlib, fontdict keys include 'size' for font size, not 'fontsize'.

2. Step 2: Check correct syntax

   Using fontdict={'size':16} correctly sets font size to 16.

3. Final Answer:

   plt.title('My Title', fontdict={'size':16}) -> Option B

4. Quick Check:

   fontdict uses 'size' key [OK]

Hint: Use 'size' key inside fontdict for font size [OK]

Common Mistakes:

• Using 'fontsize' instead of 'size'
• Using 'font' instead of 'fontdict'
• Wrong dictionary key names

3. What will be the font size of the x-axis label in the following code?

import matplotlib.pyplot as plt
plt.xlabel('X Axis', fontdict={'size':20, 'weight':'bold'})
plt.show()

medium

A. 20

B. Bold but default size

C. Default size (usually 10)

D. Error due to wrong fontdict

Solution

1. Step 1: Analyze fontdict in xlabel

   The fontdict sets 'size' to 20 and 'weight' to 'bold'.

2. Step 2: Understand effect on label

   The label will use size 20 and bold weight as specified.

3. Final Answer:

   20 -> Option A

4. Quick Check:

   fontdict size = 20 [OK]

Hint: fontdict size sets label font size directly [OK]

Common Mistakes:

• Assuming default size
• Ignoring weight property
• Thinking code causes error

4. Identify the error in this code snippet that tries to set the legend font to italic:

import matplotlib.pyplot as plt
plt.plot([1,2,3], label='Line')
plt.legend(prop={'style':'italic'})
plt.show()

medium

A. Missing plt.legend() call

B. No error, code runs fine

C. Incorrect label argument in plot

D. 'style' is not a valid font property key for legend prop

Solution

1. Step 1: Check font property keys for legend

   Valid keys include 'size', 'weight', 'family', 'style', and 'color'. 'style' is valid but must be a recognized value.

2. Step 2: Verify 'italic' usage

   'italic' is a valid style, so the key is correct. However, in matplotlib, 'style' should be set inside a FontProperties object or as a string, not directly in prop dict.

3. Step 3: Identify actual error

   The error is that 'prop' expects a FontProperties object or a dictionary with correct keys, but 'style' key is not always recognized directly in prop dict in some matplotlib versions.

4. Final Answer:

   'style' is not a valid font property key for legend prop -> Option D

5. Quick Check:

   Legend prop keys must be valid font properties [OK]

Hint: Use FontProperties for complex font styles in legend [OK]

Common Mistakes:

• Using wrong keys in prop dict
• Forgetting to import FontProperties
• Assuming all keys work directly

5. You want to create a plot with a title that uses a custom font family 'Comic Sans MS', size 18, bold weight, and blue color. Which code snippet correctly applies all these font properties?

hard

A. plt.title('My Plot', fontdict={'family':'Comic Sans MS', 'size':18, 'weight':'bold', 'color':'blue'})

B. plt.title('My Plot', fontdict={'fontfamily':'Comic Sans MS', 'fontsize':18, 'fontweight':'bold', 'fontcolor':'blue'})

C. plt.title('My Plot', font={'family':'Comic Sans MS', 'size':18, 'weight':'bold', 'color':'blue'})

D. plt.title('My Plot', fontdict={'family':'Comic Sans MS', 'fontsize':18, 'weight':'bold', 'color':'blue'})

Solution

1. Step 1: Check correct fontdict keys

   Valid keys are 'family', 'size', 'weight', and 'color'. 'fontsize' and 'fontweight' are incorrect keys here.

2. Step 2: Verify values and syntax

   plt.title('My Plot', fontdict={'family':'Comic Sans MS', 'size':18, 'weight':'bold', 'color':'blue'}) uses correct keys and values for family, size, weight, and color.

3. Final Answer:

   plt.title('My Plot', fontdict={'family':'Comic Sans MS', 'size':18, 'weight':'bold', 'color':'blue'}) -> Option A

4. Quick Check:

   Use 'family', 'size', 'weight', 'color' keys in fontdict [OK]

Hint: Use standard keys: family, size, weight, color in fontdict [OK]

Common Mistakes:

• Using 'fontsize' instead of 'size'
• Using 'fontcolor' instead of 'color'
• Passing fontdict as 'font'