np.savez() for multiple arrays in NumPy - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does np.savez() do in NumPy?

np.savez() saves multiple NumPy arrays into a single file with a .npz extension. It helps keep related arrays together for easy loading later.

beginner

How do you save multiple arrays with names using np.savez()?

You pass arrays as keyword arguments like np.savez('file.npz', arr1=array1, arr2=array2). This saves arrays with the names arr1 and arr2 inside the file.

beginner

How do you load arrays saved with np.savez()?

Use np.load('file.npz') to open the file. It returns a dictionary-like object where you can access arrays by their saved names, e.g., data['arr1'].

intermediate

What is the difference between np.savez() and np.savez_compressed()?

np.savez() saves arrays without compression, which is faster. np.savez_compressed() compresses the data to save disk space but takes more time to save and load.

intermediate

Can you save arrays without naming them in np.savez()? What happens?

Yes, you can pass arrays as positional arguments like np.savez('file.npz', array1, array2). They get saved with default names like arr_0, arr_1, etc.

What file extension does np.savez() create?

A .txt

B .npz

C .csv

D .npy

np.savez() creates an archive file with the .npz extension to store multiple arrays.

How do you access an array named 'data' after loading a file saved with np.savez()?

A data.get('data')

B data.data

C data['data']

D data.load('data')

Loading with np.load() returns a dictionary-like object. You access arrays by keys like data['data'].

Which function compresses the saved arrays to save disk space?

A np.savez_compressed()

B np.savez()

C np.save()

D np.load()

np.savez_compressed() compresses arrays when saving, reducing file size.

If you save arrays without names in np.savez(), what names do they get?

A arr_0, arr_1, ...

B array1, array2, ...

C default1, default2, ...

D No names assigned

Unnamed arrays get default names like arr_0, arr_1, etc.

Which of these is NOT true about np.savez()?

A It can save multiple arrays in one file

B It creates a file with .npz extension

C It allows naming arrays when saving

D It saves arrays as plain text

np.savez() saves arrays in a binary format, not plain text.

Explain how to save and load multiple arrays using np.savez().

Think about how you keep related things together in one box and then open it later.

Describe the difference between np.savez() and np.savez_compressed().

Consider saving files quickly versus saving space on your disk.