String type in NumPy - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a NumPy array of strings.

NumPy

import numpy as np
arr = np.array(['apple', 'banana', 'cherry'], dtype=[1])
print(arr)

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

Anp.str_

Bbool

Cfloat

Dint

Attempts:

3 left

💡 Hint

Common Mistakes

Using dtype='int' or dtype='float' for string arrays.

Using dtype=str which gives object dtype array.

Using dtype=np.str_ creates a NumPy array with string type elements.

2fill in blank

medium

Complete the code to create a fixed-length string array of length 5.

NumPy

import numpy as np
arr = np.array(['cat', 'dog', 'bird'], dtype=[1])
print(arr)
print(arr.dtype)

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

A'S5'

B'int32'

C'U10'

D'float64'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'U10' which is for Unicode strings, not byte strings.

Using numeric dtypes for string arrays.

Using dtype='S5' creates a fixed-length byte string array with length 5.

3fill in blank

hard

Fix the error in the code to create a Unicode string array.

NumPy

import numpy as np
arr = np.array(['red', 'green', 'blue'], dtype=[1])
print(arr)
print(arr.dtype)

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

A'int64'

B'S10'

C'U10'

D'bool_'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'S10' which creates byte strings, not Unicode.

Using numeric or boolean dtypes for strings.

Unicode strings in NumPy use dtype starting with 'U', so 'U10' means Unicode strings of length 10.

4fill in blank

hard

Fill both blanks to create a NumPy array of strings and check its type.

NumPy

import numpy as np
arr = np.array(['one', 'two', 'three'], dtype=[1])
print(type(arr[0]))  # Should print <class '[2]'>

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

A'U5'

Bnumpy.str_

Cstr

D'int32'

Attempts:

3 left

💡 Hint

Common Mistakes

Using Python's built-in str type instead of numpy.str_.

Using numeric dtype instead of string dtype.

Using dtype='U5' creates Unicode strings of length 5. The type of each element is numpy.str_.

5fill in blank

hard

Fill all three blanks to create a fixed-length byte string array and convert it to Unicode strings.

NumPy

import numpy as np
byte_arr = np.array(['a', 'bb', 'ccc'], dtype=[1])
unicode_arr = byte_arr.astype([2])
print(unicode_arr)
print(unicode_arr.dtype == [3])

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

A'S3'

Bstr

C'U3'

Dnp.str_

Attempts:

3 left

💡 Hint

Common Mistakes

Using Python's str instead of np.str_.

Confusing byte string dtype 'S3' with Unicode dtype 'U3'.

We create a byte string array with dtype 'S3'. Then convert it to Unicode strings using astype(np.str_). The resulting dtype is 'U3'.