Memory-mapped files with np.memmap in NumPy - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a memory-mapped file named 'data.dat' with shape (100,) and dtype float32.

NumPy

import numpy as np
mmap_array = np.memmap('data.dat', dtype=[1], mode='w+', shape=(100,))

Drag options to blanks, or click blank then click option'

A'int64'

B'float32'

C'bool'

D'complex128'

Attempts:

3 left

💡 Hint

Common Mistakes

Using an integer dtype instead of float32.

Forgetting to specify the dtype parameter.

The dtype float32 matches the requirement for the memory-mapped file.

2fill in blank

medium

Complete the code to open an existing memory-mapped file 'data.dat' in read-only mode.

NumPy

mmap_read = np.memmap('data.dat', dtype='float32', mode=[1], shape=(100,))

Drag options to blanks, or click blank then click option'

A'r'

B'w+'

C'c'

D'w'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'w+' which allows writing and truncates the file.

Using 'c' which allows copy-on-write but not pure read-only.

The mode 'r' opens the file in read-only mode without allowing changes.

3fill in blank

hard

Fix the error in the code to correctly create a memory-mapped file with shape (50, 2).

NumPy

mmap_array = np.memmap('data2.dat', dtype='float64', mode='w+', shape=[1])

Drag options to blanks, or click blank then click option'

A50, 2

B[50, 2]

C(50, 2)

D50

Attempts:

3 left

💡 Hint

Common Mistakes

Using a list instead of a tuple for shape.

Passing multiple arguments instead of a single tuple.

The shape must be a tuple, so (50, 2) is correct.

4fill in blank

hard

Fill both blanks to create a memory-mapped file 'data3.dat' with dtype int32 and shape (10, 10).

NumPy

mmap_file = np.memmap('data3.dat', dtype=[1], mode='w+', shape=[2])

Drag options to blanks, or click blank then click option'

A'int32'

B'float64'

C(10, 10)

D[10, 10]

Attempts:

3 left

💡 Hint

Common Mistakes

Using float64 instead of int32 for dtype.

Using a list instead of a tuple for shape.

The dtype should be int32 and the shape a tuple (10, 10).

5fill in blank

hard

Fill all three blanks to open an existing memory-mapped file 'data4.dat' with dtype float64, shape (5, 5), in copy-on-write mode.

NumPy

mmap_copy = np.memmap('data4.dat', dtype=[1], mode=[2], shape=[3])

Drag options to blanks, or click blank then click option'

A'float32'

B'c'

C(5, 5)

D'float64'

Attempts:

3 left

💡 Hint

Common Mistakes

Using float32 instead of float64 for dtype.

Using 'w+' or 'r' instead of 'c' for mode.

Using a list instead of a tuple for shape.

The dtype is float64, mode is 'c' for copy-on-write, and shape is (5, 5).