Line styles (solid, dashed, dotted) in Matplotlib - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to plot a solid line using matplotlib.

Matplotlib

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

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

A"--"

B"-"

C":"

D"-."

Attempts:

3 left

💡 Hint

Common Mistakes

Using "--" which creates a dashed line instead of solid.

Using ":" which creates a dotted line.

The linestyle "-" creates a solid line in matplotlib.

2fill in blank

medium

Complete the code to plot a dashed line using matplotlib.

Matplotlib

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

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

A"-"

B":"

C"--"

D"-."

Attempts:

3 left

💡 Hint

Common Mistakes

Using "-" which creates a solid line instead of dashed.

Using ":" which creates a dotted line.

The linestyle "--" creates a dashed line in matplotlib.

3fill in blank

hard

Fix the error in the code to plot a dotted line using matplotlib.

Matplotlib

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

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

A"-."

B"-"

C"--"

D":"

Attempts:

3 left

💡 Hint

Common Mistakes

Using "-" or "--" which create solid or dashed lines instead of dotted.

Repeating the same option twice.

The linestyle ":" creates a dotted line in matplotlib.

4fill in blank

hard

Fill both blanks to create a plot with a dashed line and label it 'Dashed'.

Matplotlib

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

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

A"--"

B"Dotted"

C"Dashed"

D"-"

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong linestyle for dashed lines.

Labeling the line incorrectly.

Use linestyle "--" for dashed line and label it "Dashed" for the legend.

5fill in blank

hard

Fill all three blanks to create a plot with a dotted line, label it 'Dotted', and set the line width to 2.

Matplotlib

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

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

A"--"

B"Dotted"

C2

D":"

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong linestyle for dotted lines.

Forgetting to set the linewidth correctly.

Use linestyle ":" for dotted line, label it "Dotted", and set linewidth to 2 for thicker line.

Practice

1. Which linestyle value in matplotlib creates a solid line?

easy

A. "-"

B. "--"

C. ":"

D. "-."

Solution

1. Step 1: Understand line style symbols in matplotlib

   In matplotlib, the linestyle parameter uses symbols: "-" for solid, "--" for dashed, ":" for dotted, and "-." for dash-dot.

2. Step 2: Match symbol to solid line

   The symbol "-" represents a solid line style.

3. Final Answer:

   "-" -> Option A

4. Quick Check:

   Solid line = "-" [OK]

Hint: Solid line uses a single dash "-" [OK]

Common Mistakes:

• Confusing dashed "--" with solid
• Using ":" for solid line
• Mixing dash-dot "-." with solid

2. Which of the following is the correct syntax to plot a dashed line using matplotlib.pyplot?

easy

A. plt.plot(x, y, linestyle='-')

B. plt.plot(x, y, linestyle=':')

C. plt.plot(x, y, linestyle='--')

D. plt.plot(x, y, linestyle='solid')

Solution

1. Step 1: Recall linestyle values for dashed lines

   Dashed lines in matplotlib are specified by the string "--" or the word "dashed".

2. Step 2: Identify correct syntax

   Among the options, only linestyle='--' correctly sets a dashed line.

3. Final Answer:

   plt.plot(x, y, linestyle='--') -> Option C

4. Quick Check:

   Dashed line = "--" [OK]

Hint: Dashed line uses double dash "--" [OK]

Common Mistakes:

• Using single dash '-' for dashed line
• Using ':' which is dotted line
• Using 'solid' string incorrectly

3. What will be the line style of the plot generated by this code?

import matplotlib.pyplot as plt
x = [1, 2, 3]
y = [2, 3, 5]
plt.plot(x, y, linestyle=':')
plt.show()

medium

A. Dotted line

B. Dashed line

C. Solid line

D. Dash-dot line

Solution

1. Step 1: Identify linestyle parameter value

   The code uses linestyle=':', which in matplotlib means a dotted line.

2. Step 2: Understand line style mapping

   "-" is solid, "--" is dashed, ":" is dotted, and "-." is dash-dot.

3. Final Answer:

   Dotted line -> Option A

4. Quick Check:

   Colon ":" means dotted line [OK]

Hint: Colon ":" means dotted line style [OK]

Common Mistakes:

• Thinking ':' is dashed line
• Confusing dash-dot '-.' with dotted
• Assuming default solid line

4. The following code is intended to plot a dashed line but does not work as expected. What is the error?

import matplotlib.pyplot as plt
x = [0, 1, 2]
y = [0, 1, 4]
plt.plot(x, y, linestyle='dash')
plt.show()

medium

A. The list y has wrong values

B. The linestyle value 'dash' is invalid; use '--' instead

C. Missing plt.show() call

D. The variable names x and y are incorrect

Solution

1. Step 1: Check valid linestyle values in matplotlib

   Matplotlib accepts 'solid', 'dashed', 'dashdot', 'dotted' as strings or symbols like '--', '-.', ':'. The string 'dash' is invalid.

2. Step 2: Identify the error

   The code uses linestyle='dash', which is not a valid linestyle value. Use '--' for dashed lines.

3. Final Answer:

   The linestyle value 'dash' is invalid; use '--' instead -> Option B

4. Quick Check:

   Invalid 'dash'; use '--' [OK]

Hint: 'dash' invalid for dashed; use '--' [OK]

Common Mistakes:

• Assuming 'dash' string works
• Thinking plt.show() is missing
• Blaming variable names or data values

5. You want to plot two lines on the same graph: the first one solid and the second one dotted. Which code correctly sets these line styles?

hard

A. plt.plot(x, y1, linestyle='-.')
plt.plot(x, y2, linestyle=':')

B. plt.plot(x, y1, linestyle=':')
plt.plot(x, y2, linestyle='-')

C. plt.plot(x, y1, linestyle='-')
plt.plot(x, y2, linestyle='--')

D. plt.plot(x, y1, linestyle='-')
plt.plot(x, y2, linestyle=':')

Solution

1. Step 1: Identify line styles for solid and dotted

   Solid line uses "-" and dotted line uses ":" in matplotlib.

2. Step 2: Match code to required styles

   plt.plot(x, y1, linestyle='-') plt.plot(x, y2, linestyle=':') uses linestyle='-' for the first line (solid) and linestyle=':' for the second line (dotted), which is correct.

3. Final Answer:

   plt.plot(x, y1, linestyle='-') and plt.plot(x, y2, linestyle=':') -> Option D

4. Quick Check:

   Solid = '-', Dotted = ':' [OK]

Hint: Solid '-' and dotted ':' line styles together [OK]

Common Mistakes:

• Mixing dashed '--' with dotted ':'
• Using dash-dot '-.' instead of dotted
• Swapping line styles order