NumPy: Count the lowest index of "P" in a given array, element-wise

NumPy String: Exercise-16 with Solution

Write a NumPy program to count the lowest index of "P" in a given array, element-wise.

Sample Solution:-

Python Code:

import numpy as np
x1 = np.array(['Python', 'PHP', 'JS', 'EXAMPLES', 'HTML'], dtype=np.str)
print("\nOriginal Array:")
print("count the lowest index of ‘P’:")
r = np.char.find(x1, "P")

Sample Input:

(['Python', 'PHP', 'JS', 'EXAMPLES', 'HTML'], dtype=np.str)

Sample Output:

Original Array:
['Python' 'PHP' 'JS' 'EXAMPLES' 'HTML']
count the lowest index of ‘P’:
[ 0  0 -1  4 -1]

Pictorial Presentation:

NumPy String: Count the lowest index of

Python Code Editor:

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Python: Tips of the Day

Getting the last element of a list:

some_list[-1] is the shortest and most Pythonic.

In fact, you can do much more with this syntax. The some_list[-n] syntax gets the nth-to-last element. So some_list[-1] gets the last element, some_list[-2] gets the second to last, etc, all the way down to some_list[-len(some_list)], which gives you the first element.

You can also set list elements in this way. For instance:

>>> some_list = [1, 2, 3]
>>> some_list[-1] = 5 # Set the last element
>>> some_list[-2] = 3 # Set the second to last element
>>> some_list
[1, 3, 5]

Note that getting a list item by index will raise an IndexError if the expected item doesn't exist. This means that some_list[-1] will raise an exception if some_list is empty, because an empty list can't have a last element.

Ref: https://bit.ly/3d8TfFP