Comparison operations in NumPy - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the comparison operation arr1 > arr2 do in NumPy?

It compares each element of arr1 with the corresponding element of arr2 and returns a boolean array where each value is True if the element in arr1 is greater than the element in arr2, otherwise False.

intermediate

How does NumPy handle comparison operations between arrays of different shapes?

NumPy uses broadcasting rules to compare arrays of different shapes. It stretches the smaller array along dimensions of size 1 to match the larger array's shape, then performs element-wise comparison.

beginner

What is the output type of a comparison operation between two NumPy arrays?

The output is a NumPy array of boolean values (True or False) indicating the result of the comparison for each element.

beginner

Which comparison operators can be used element-wise on NumPy arrays?

You can use <, <=, >, >=, ==, and != for element-wise comparisons on NumPy arrays.

intermediate

How can you find if any element in a NumPy boolean array is True after a comparison?

Use the numpy.any() function on the boolean array. It returns True if at least one element is True, otherwise False.

What does arr == 5 return if arr is a NumPy array?

A A boolean array showing where elements equal 5

B A single boolean value

C An array of integers

D An error

The operation compares each element to 5 and returns a boolean array with True where elements equal 5.

Which operator checks if elements in one array are not equal to another array?

A ==

B !=

C >=

D <

The != operator returns True where elements differ between arrays.

If arr1 has shape (3,1) and arr2 has shape (3,4), what happens when you do arr1 < arr2?

A An error occurs due to shape mismatch

B arr2 is reshaped to (3,1)

C Only first column is compared

D Broadcasting stretches arr1 to (3,4) and compares element-wise

NumPy broadcasts arr1 to match arr2's shape and compares each element.

What type of array results from arr1 >= arr2?

A Float array

B Integer array

C Boolean array

D String array

Comparison operations produce boolean arrays indicating True or False per element.

How do you check if any element in a boolean NumPy array is True?

A numpy.any()

B numpy.all()

C sum()

D len()

numpy.any() returns True if at least one element is True.

Explain how element-wise comparison works between two NumPy arrays.

Think about how NumPy compares each element and what it returns.

Describe how to use comparison operators to filter data in a NumPy array.

Consider how True/False arrays help pick data.