NumPy: Replace a specific character with another in a given array of string values

Last update on April 29 2025 12:55:18 (UTC/GMT +8 hours)

20. Replace Specific Characters in Strings

Write a NumPy program to replace a specific character with another in a given array of string values.

Sample Solution:

Python Code:

# Importing necessary library
import numpy as np 

# Creating a NumPy array containing strings
str1 = np.array([['Python-NumPy-Exercises'], ['-Python-']])

# Displaying the original array of string values
print("Original array of string values:") 
print(str1)

# Replacing '-' with '=' character in the array of string values using np.char.replace() and np.char.strip()
print("\nReplace '-' with '=' character in the said array of string values:")
print(np.char.strip(np.char.replace(str1, '-', '==')))

# Replacing '-' with ' ' character in the array of string values using np.char.replace() and np.char.strip()
print("\nReplace '-' with ' ' character in the said array of string values:")
print(np.char.strip(np.char.replace(str1, '-', ' ')))

Sample Output:

Original array of string values:
[['Python-NumPy-Exercises']
 ['-Python-']]

Replace '-' with '=' character in the said array of string values:
[['Python==NumPy==Exercises']
 ['==Python==']]

Replace '-' with ' ' character in the said array of string values:
[['Python NumPy Exercises']
 ['Python']]

Explanation:

In the above code –

str1 = np.array([['Python-NumPy-Exercises'], ['-Python-']]): This creates a NumPy array str1 containing two strings. The first string is 'Python-NumPy-Exercises' and the second is '-Python-'. Each string is contained within its own array.

np.char.strip(np.char.replace(str1, '-', '==')): This line replaces all occurrences of '-' in the strings of str1 with '==' and then strips leading and trailing whitespace from each resulting string.

np.char.strip(np.char.replace(str1, '-', ' ')): This line replaces all occurrences of '-' in the strings of str1 with a space and then strips leading and trailing whitespace from each resulting string.

For more Practice: Solve these Related Problems:

Create a function that replaces a specified character (e.g., '-') with another (e.g., '=') in each element of a string array using np.char.replace.
Implement a solution that performs multiple replacements in a single pass using chained np.char.replace calls.
Test the function on an array containing various punctuation marks to replace them with a space.
Combine the replacement operation with a trim to remove any unwanted extra characters introduced during the process.

Go to:

Previous: Write a NumPy program to add two zeros to the beginning of each element of a given array of string values.
Next: Write a NumPy program to count a given word in each row of a given array of string values.

Python-Numpy Code Editor:

Have another way to solve this solution? Contribute your code (and comments) through Disqus.