np.sort() for sorting arrays in NumPy - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does np.sort() do in NumPy?

np.sort() sorts the elements of an array in ascending order and returns a new sorted array without changing the original array.

intermediate

How can you sort a 2D NumPy array by rows using np.sort()?

Use np.sort(array, axis=1) to sort each row independently in ascending order.

beginner

Does np.sort() modify the original array?

No, np.sort() returns a new sorted array and leaves the original array unchanged.

intermediate

What parameter in np.sort() controls the sorting axis?

The axis parameter controls which axis to sort along. For example, axis=0 sorts each column, axis=1 sorts each row.

intermediate

How do you sort a NumPy array in descending order using np.sort()?

Sort the array in ascending order with np.sort() and then reverse it using slicing: np.sort(array)[::-1].

What does np.sort() return?

A A new sorted array

B The original array sorted in place

C A boolean indicating if the array is sorted

D The sum of array elements

np.sort() returns a new sorted array and does not change the original array.

How do you sort each column of a 2D array using np.sort()?

A <code>np.sort(array, axis=0)</code>

B <code>np.sort(array, axis=1)</code>

C <code>np.sort(array)</code>

D <code>np.sort(array, axis=2)</code>

Setting axis=0 sorts each column independently.

Which of these sorts an array in descending order using np.sort()?

A <code>np.sort(array, axis=-1)</code>

B <code>np.sort(array, descending=True)</code>

C <code>np.sort(array, reverse=True)</code>

D <code>np.sort(array)[::-1]</code>

NumPy's np.sort() does not have a descending parameter, so you sort ascending then reverse with slicing.

If you call np.sort(array) without axis on a 2D array, what happens?

A Each row is sorted independently

B Each column is sorted independently

C The array is flattened and sorted

D An error is raised

Without specifying axis, the array is flattened to 1D and sorted.

Does np.sort() change the original array?

A Yes, it sorts the original array in place

B No, it returns a new sorted array

C Only if you set <code>inplace=True</code>

D Only for 1D arrays

np.sort() always returns a new sorted array and does not modify the original.

Explain how to use np.sort() to sort a 2D array by rows and by columns.

Think about which axis represents rows and which represents columns.

Describe how to sort a NumPy array in descending order using np.sort().

Consider how to reverse a list or array in Python.