Array creation (array, arange, linspace) in Data Analysis Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of NumPy arange with float step

What is the output of this code snippet?

import numpy as np
result = np.arange(0, 1, 0.3)
print(result)

Data Analysis Python

import numpy as np
result = np.arange(0, 1, 0.3)
print(result)

A [0. 0.3 0.6 0.9 1.0]

B [0. 0.3 0.6 0.9 1.2]

C [0. 0.3 0.6]

D [0. 0.3 0.6 0.9]

💡 Hint

Remember that arange excludes the stop value and uses step increments.

np.arange starts at 0 and adds 0.3 repeatedly until it reaches or passes 1. It stops before 1, so 1 is not included.

❓ data_output

intermediate

Number of elements in linspace with endpoint=False

How many elements does this array have?

import numpy as np
arr = np.linspace(2, 10, 5, endpoint=False)
print(len(arr))

Data Analysis Python

import numpy as np
arr = np.linspace(2, 10, 5, endpoint=False)
print(len(arr))

A 6

B 5

C 4

D 10

💡 Hint

The number of points is controlled by the third argument, regardless of endpoint.

linspace creates exactly the number of points specified by the third argument, here 5, even if endpoint is False.

❓ visualization

advanced

Visual difference between arange and linspace

Which plot correctly shows the difference between np.arange(0, 1, 0.2) and np.linspace(0, 1, 6)?

Data Analysis Python

import numpy as np
import matplotlib.pyplot as plt
x1 = np.arange(0, 1, 0.2)
x2 = np.linspace(0, 1, 6)
plt.plot(x1, np.zeros_like(x1), 'o', label='arange')
plt.plot(x2, np.ones_like(x2), 'x', label='linspace')
plt.legend()
plt.show()

A Plot with 5 'o' points at 0,0.2,0.4,0.6,0.8 and 6 'x' points at 0,0.2,0.4,0.6,0.8,1

B Plot with 6 'o' points at 0,0.2,0.4,0.6,0.8,1 and 5 'x' points at 0,0.25,0.5,0.75,1

C Plot with 5 'o' points at 0,0.25,0.5,0.75,1 and 6 'x' points at 0,0.2,0.4,0.6,0.8,1

D Plot with 6 'o' points at 0,0.2,0.4,0.6,0.8,1 and 6 'x' points at 0,0.2,0.4,0.6,0.8,1

💡 Hint

arange excludes the stop value, linspace includes it by default.

np.arange(0,1,0.2) produces 5 points excluding 1, np.linspace(0,1,6) produces 6 points including 1.

🧠 Conceptual

advanced

Behavior of np.linspace with num=1

What is the output of this code?

import numpy as np
arr = np.linspace(5, 10, 1)
print(arr)

Data Analysis Python

import numpy as np
arr = np.linspace(5, 10, 1)
print(arr)

A [5.]

B [10.]

C [7.5]

D []

💡 Hint

When num=1, linspace returns the start value only.

np.linspace with num=1 returns an array with the start value only, ignoring the stop value.

🔧 Debug

expert

Identify the error in this array creation code

What error does this code raise?

import numpy as np
arr = np.arange(0, 10, 0)
print(arr)

Data Analysis Python

import numpy as np
arr = np.arange(0, 10, 0)
print(arr)

A TypeError: step must be int or float

B SyntaxError: invalid syntax

C ValueError: zero step size

D No error, prints array from 0 to 9

💡 Hint

Step size cannot be zero in range or arange functions.

np.arange raises ValueError if step is zero because it cannot progress through the range.