np.abs() for absolute values in NumPy - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of np.abs() on mixed array

What is the output of this code?

import numpy as np
arr = np.array([-3, 0, 4, -7])
result = np.abs(arr)
print(result)

NumPy

import numpy as np
arr = np.array([-3, 0, 4, -7])
result = np.abs(arr)
print(result)

A [3 0 4 7]

B [-3 0 4 -7]

C [3 0 -4 7]

D [0 3 4 7]

💡 Hint

np.abs() returns the absolute value of each element in the array.

np.abs() changes each number to its positive value without changing zero.

❓ data_output

intermediate

Absolute values of a 2D numpy array

Given this 2D array, what is the output of np.abs() applied to it?

import numpy as np
arr = np.array([[1, -2], [-3, 4]])
result = np.abs(arr)
print(result)

NumPy

import numpy as np
arr = np.array([[1, -2], [-3, 4]])
result = np.abs(arr)
print(result)

A

[[-1 2]
 [3 -4]]

B

[[1 -2]
 [-3 4]]

C

[[1 2]
 [3 4]]

D

[[1 2]
 [-3 4]]

💡 Hint

np.abs() works element-wise on arrays of any shape.

Each element is converted to its positive value, keeping the shape intact.

🧠 Conceptual

advanced

Effect of np.abs() on complex numbers

What does np.abs() return when applied to a numpy array of complex numbers?

import numpy as np
arr = np.array([3+4j, 1-1j])
result = np.abs(arr)
print(result)

NumPy

import numpy as np
arr = np.array([3+4j, 1-1j])
result = np.abs(arr)
print(result)

A [5. 1.41421356]

B [3.+4.j 1.-1.j]

C [7.+0.j 2.+0.j]

D [-3.-4.j -1.+1.j]

💡 Hint

np.abs() returns the magnitude (distance from zero) for complex numbers.

For complex numbers, np.abs() returns the magnitude calculated as sqrt(real^2 + imag^2).

🔧 Debug

advanced

Identify the error in np.abs() usage

What error will this code raise?

import numpy as np
arr = np.array(['-3', '4', '-5'])
result = np.abs(arr)
print(result)

NumPy

import numpy as np
arr = np.array(['-3', '4', '-5'])
result = np.abs(arr)
print(result)

A SyntaxError: invalid syntax

B ValueError: invalid literal for int() with base 10

C No error, output: [3 4 5]

D TypeError: bad operand type for abs(): 'str'

💡 Hint

np.abs() expects numeric types, not strings.

np.abs() cannot process string arrays directly and raises a TypeError.

🚀 Application

expert

Using np.abs() to find max absolute difference

Given two numpy arrays, which option correctly finds the maximum absolute difference between their elements?

import numpy as np
a = np.array([1, -3, 5])
b = np.array([4, -1, -6])
max_diff = ???
print(max_diff)

NumPy

import numpy as np
a = np.array([1, -3, 5])
b = np.array([4, -1, -6])
max_diff = ???
print(max_diff)

A np.abs(np.max(a) - np.max(b))

B np.max(np.abs(a - b))

C np.max(a) - np.min(b)

D np.abs(np.min(a) - np.min(b))

💡 Hint

Find the absolute difference element-wise, then get the max.

Subtract arrays element-wise, take absolute values, then find the max value.