Line plots in Data Analysis Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of a simple line plot code

What will be the output of this Python code using matplotlib?

Data Analysis Python

import matplotlib.pyplot as plt
x = [1, 2, 3, 4]
y = [10, 20, 25, 30]
plt.plot(x, y)
plt.show()

A A bar chart with bars at x=1 to 4 with heights 10 to 30

B A line plot showing points connected by a line from (1,10) to (4,30)

C A scatter plot showing only points at (1,10), (2,20), (3,25), (4,30) without lines

D An empty plot with no data shown

💡 Hint

plt.plot() connects points with lines by default.

The plt.plot() function draws a line plot connecting the points defined by x and y lists.

❓ data_output

intermediate

Number of lines in a multi-line plot

Given this code, how many separate lines will appear in the plot?

Data Analysis Python

import matplotlib.pyplot as plt
x = [0, 1, 2, 3]
y1 = [1, 3, 2, 4]
y2 = [4, 2, 3, 1]
plt.plot(x, y1)
plt.plot(x, y2)
plt.show()

A 2

B 4

C 3

D 1

💡 Hint

Each plt.plot() call adds one line to the plot.

Two plt.plot() calls create two separate lines on the same plot.

🔧 Debug

advanced

Identify the error in this line plot code

What error will this code produce when run?

Data Analysis Python

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

A No error, plot will display correctly

B TypeError: unsupported operand type(s) for +

C SyntaxError: invalid syntax

D ValueError: x and y must have same first dimension

💡 Hint

x and y lists must be the same length for plotting.

The x list has 3 elements but y has 2, causing a ValueError.

❓ visualization

advanced

Effect of linestyle parameter in line plots

Which option shows the correct line style for this code?

Data Analysis Python

import matplotlib.pyplot as plt
x = [0, 1, 2, 3]
y = [3, 1, 4, 2]
plt.plot(x, y, linestyle='--')
plt.show()

A No line, only points shown

B A solid line connecting the points

C A dashed line connecting the points

D A dotted line connecting the points

💡 Hint

The linestyle='--' means dashed line.

The linestyle parameter '--' creates a dashed line style.

🚀 Application

expert

Interpreting trends from a line plot

A line plot shows monthly sales over a year with a steady upward slope except for a dip in July. What does this indicate?

A Sales generally increased over the year but dropped in July

B Sales decreased steadily all year

C Sales were constant all year with no changes

D Sales peaked in July and dropped afterwards

💡 Hint

Look at the slope and dips in the line plot.

An upward slope means increasing sales; a dip in July means a temporary drop.