NumPy: Extract all the rows from a given array where a specific column starts with a given character

Last update on August 29 2025 12:48:58 (UTC/GMT +8 hours)

Extract rows based on column starting character.

Write a NumPy program to extract all the rows from a given array where a specific column starts with a given character.

Sample array:
[['01' 'V' 'Debby Pramod']
['02' 'V' 'Artemiy Ellie']
['03' 'V' 'Baptist Kamal']
['04' 'V' 'Lavanya Davide']
['05' 'V' 'Fulton Antwan']
['06' 'V' 'Euanthe Sandeep']
['07' 'V' 'Endzela Sanda']
['08' 'V' 'Victoire Waman']
['09' 'V' 'Briar Nur']
['10' 'V' 'Rose Lykos']]

Sample Solution:

Python Code:

# Importing NumPy library
import numpy as np

# Setting printing options to display arrays with a maximum line width of 100
np.set_printoptions(linewidth=100)

# Creating a NumPy array containing student data
student =  np.array([
    ['01', 'V', 'Debby Pramod'],
    ['02', 'V', 'Artemiy Ellie'],
    ['03', 'V', 'Baptist Kamal'],
    ['04', 'V', 'Lavanya Davide'],
    ['05', 'V', 'Fulton Antwan'],
    ['06', 'V', 'Euanthe Sandeep'],
    ['07', 'V', 'Endzela Sanda'],
    ['08', 'V', 'Victoire Waman'],
    ['09', 'V', 'Briar Nur'],
    ['10', 'V', 'Rose Lykos']
])

# Displaying the original array
print("Original array:")
print(student)

# Searching for student names starting with a specific character ('E')
char = 'E'
result = student[np.char.startswith(student[:, 2], char)]
print("\nStudent name starting with", char, ":")
print(result)

# Searching for student IDs starting with a specific character ('1')
char = '1'
result = student[np.char.startswith(student[:, 0], char)]
print("\nStudent id starting with", char, ":")
print(result)

Sample Output:

Original array:
[['01' 'V' 'Debby Pramod']
 ['02' 'V' 'Artemiy Ellie']
 ['03' 'V' 'Baptist Kamal']
 ['04' 'V' 'Lavanya Davide']
 ['05' 'V' 'Fulton Antwan']
 ['06' 'V' 'Euanthe Sandeep']
 ['07' 'V' 'Endzela Sanda']
 ['08' 'V' 'Victoire Waman']
 ['09' 'V' 'Briar Nur']
 ['10' 'V' 'Rose Lykos']]

Student name starting with E :
[['06' 'V' 'Euanthe Sandeep']
 ['07' 'V' 'Endzela Sanda']]

Student id starting with 1 :
[['10' 'V' 'Rose Lykos']]

For more Practice: Solve these Related Problems:

Write a NumPy program to filter rows from a 2D array of strings where a specific column’s value starts with a given character using np.char.startswith.
Create a function that returns the indices of rows whose specified column matches a given starting letter, employing vectorized string operations.
Implement a solution that uses a boolean mask based on np.char.startswith to extract and return the matching rows.
Test the extraction function on arrays with varying cases to ensure the filtering can be adjusted for case sensitivity.

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