Line colors and width in Matplotlib - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the line color to red.

Matplotlib

import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [4, 5, 6], color=[1])
plt.show()

Drag options to blanks, or click blank then click option'

A'blue'

B'yellow'

C'green'

D'red'

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the color name.

Using an invalid color name.

The color parameter sets the line color. Here, 'red' makes the line red.

2fill in blank

medium

Complete the code to set the line width to 3.

Matplotlib

import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [4, 5, 6], linewidth=[1])
plt.show()

Drag options to blanks, or click blank then click option'

A3

B1

C5

D0.5

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string instead of a number.

Choosing a very small number that makes the line hard to see.

The linewidth parameter controls the thickness of the line. Setting it to 3 makes the line thicker.

3fill in blank

hard

Fix the error in the code to set the line color to blue.

Matplotlib

import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [4, 5, 6], color=[1])
plt.show()

Drag options to blanks, or click blank then click option'

A'blue'

BBLUE

C"blue"

Dblue

Attempts:

3 left

💡 Hint

Common Mistakes

Using the color name without quotes.

Using uppercase letters without quotes.

The color value must be a string with quotes. 'blue' or "blue" works, but here only one option is correct to avoid ambiguity.

4fill in blank

hard

Fill both blanks to set the line color to green and width to 2.

Matplotlib

import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [4, 5, 6], color=[1], linewidth=[2])
plt.show()

Drag options to blanks, or click blank then click option'

A'green'

B1

C2

D'red'

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up color and linewidth values.

Using numbers for color or strings for linewidth.

Use 'green' for the color and 2 for the line width to get a green line with thickness 2.

5fill in blank

hard

Fill all three blanks to create a blue line with width 4 and label it 'My Line'.

Matplotlib

import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [4, 5, 6], color=[1], linewidth=[2], label=[3])
plt.legend()
plt.show()

Drag options to blanks, or click blank then click option'

A'blue'

B4

C'My Line'

D'red'

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the label.

Using a string for linewidth or number for color.

Set color='blue', linewidth=4, and label='My Line' to create a thick blue line with a label shown in the legend.

Practice

1. Which parameter in matplotlib.pyplot.plot() changes the color of the line?

easy

A. linestyle

B. color

C. linewidth

D. marker

Solution

1. Step 1: Understand the purpose of parameters in plot()

   The color parameter sets the line color, while linewidth changes thickness.

2. Step 2: Identify the parameter for color

   Among the options, only color directly changes the line color.

3. Final Answer:

   color -> Option B

4. Quick Check:

   Line color = color [OK]

Hint: Remember: color changes color, linewidth changes thickness [OK]

Common Mistakes:

• Confusing linewidth with color
• Using linestyle to change color
• Trying to use marker for color

2. Which of the following is the correct syntax to set a red line with thickness 3 in matplotlib.pyplot.plot()?

easy

A. plt.plot(x, y, color='red', linewidth=3)

B. plt.plot(x, y, linewidth='red', color=3)

C. plt.plot(x, y, color=3, linewidth='red')

D. plt.plot(x, y, width=3, color='red')

Solution

1. Step 1: Check parameter names and values

   The correct parameters are color with a color string and linewidth with a number.

2. Step 2: Validate plt.plot(x, y, color='red', linewidth=3) syntax

   plt.plot(x, y, color='red', linewidth=3) uses color='red' and linewidth=3, which is correct syntax.

3. Final Answer:

   plt.plot(x, y, color='red', linewidth=3) -> Option A

4. Quick Check:

   Correct parameter names and types = plt.plot(x, y, color='red', linewidth=3) [OK]

Hint: Use color='colorname' and linewidth=number [OK]

Common Mistakes:

• Swapping color and linewidth values
• Using wrong parameter names like width
• Passing numbers as color

3. What will be the color and thickness of the line drawn by this code?

import matplotlib.pyplot as plt
x = [1, 2, 3]
y = [4, 5, 6]
plt.plot(x, y, color='green', linewidth=5)
plt.show()

medium

A. Blue line with thickness 5

B. Green line with thickness 1

C. Green line with thickness 5

D. Red line with thickness 5

Solution

1. Step 1: Analyze color parameter

   The code sets color='green', so the line color is green.

2. Step 2: Analyze linewidth parameter

   The code sets linewidth=5, so the line thickness is 5 (thicker than default).

3. Final Answer:

   Green line with thickness 5 -> Option C

4. Quick Check:

   color='green' and linewidth=5 = Green line with thickness 5 [OK]

Hint: Check color and linewidth values directly in plot() [OK]

Common Mistakes:

• Ignoring linewidth value
• Assuming default thickness
• Confusing color names

4. Identify the error in this code snippet:

import matplotlib.pyplot as plt
plt.plot([1,2,3], [4,5,6], color=5, linewidth='thick')
plt.show()

medium

A. Missing plt.show() call

B. color should be a number, linewidth should be a string

C. color and linewidth parameters are correct

D. color should be a string, linewidth should be a number

Solution

1. Step 1: Check color parameter type

   color must be a color name string or code, not a number like 5.

2. Step 2: Check linewidth parameter type

   linewidth must be a number (int or float), not a string like 'thick'.

3. Final Answer:

   color should be a string, linewidth should be a number -> Option D

4. Quick Check:

   Parameter types must match expected types [OK]

Hint: color='name', linewidth=number; no numbers for color [OK]

Common Mistakes:

• Passing numbers as color
• Passing strings as linewidth
• Ignoring type errors

5. You want to plot two lines on the same graph: one thick blue line and one thin orange line. Which code correctly does this?

hard

A. plt.plot(x, y1, color='blue', linewidth=6)
plt.plot(x, y2, color='orange', linewidth=1)

B. plt.plot(x, y1, color='orange', linewidth=6)
plt.plot(x, y2, color='blue', linewidth=1)

C. plt.plot(x, y1, linewidth='thick', color='blue')
plt.plot(x, y2, linewidth='thin', color='orange')

D. plt.plot(x, y1, color=6, linewidth='blue')
plt.plot(x, y2, color=1, linewidth='orange')

Solution

1. Step 1: Match colors to lines

   The thick line should be blue, so color='blue' with large linewidth for y1.

2. Step 2: Match thickness and color for second line

   The thin line should be orange, so color='orange' with small linewidth for y2.

3. Step 3: Validate parameter types

   plt.plot(x, y1, color='blue', linewidth=6) plt.plot(x, y2, color='orange', linewidth=1) uses correct parameter names and types for both lines.

4. Final Answer:

   plt.plot(x, y1, color='blue', linewidth=6) plt.plot(x, y2, color='orange', linewidth=1) -> Option A

5. Quick Check:

   Correct colors and linewidths = plt.plot(x, y1, color='blue', linewidth=6) plt.plot(x, y2, color='orange', linewidth=1) [OK]

Hint: Assign color and linewidth clearly for each line [OK]

Common Mistakes:

• Swapping colors and linewidths
• Using strings for linewidth
• Passing numbers as colors