How to Remove Bad Words from Chat Scripts

What will you learn?

Discover how to effectively filter out and remove inappropriate language or bad words from chat messages using Python. Learn the importance of maintaining a respectful and safe environment in chat applications.

Introduction to the Problem and Solution

In the realm of chat applications, ensuring a safe and respectful environment for all users is paramount. One common challenge faced is the occurrence of bad language or inappropriate words within chat messages. To address this issue, we can develop a script that automatically filters out such words before displaying the messages.

By employing string manipulation techniques and maintaining a list of prohibited words, we can create a solution that enhances user experience by promoting positive interactions within the chat platform.


# Import regular expressions module
import re

def filter_bad_words(chat_message):
    # List of bad words to be filtered out
    bad_words = ["bad_word1", "bad_word2", "bad_word3"]

    # Regular expression pattern for matching bad words in the message
    regex_pattern = r"\b" + "|".join(bad_words) + r"\b"

    # Replace any occurrence of bad words with asterisks (or any other action)
    filtered_message = re.sub(regex_pattern, "***", chat_message, flags=re.IGNORECASE)

    return filtered_message

# Test the function with a sample chat message
chat_message = "Hey there! This is a test containing a bad_word1."
filtered_chat = filter_bad_words(chat_message)

# Copyright PHD

Note: For an extensive list of bad words or more advanced filtering techniques, consider utilizing external libraries or APIs available online.


  • Importing re Module: We import Python’s built-in re module for effective handling of regular expressions.
  • Defining filter_bad_words Function: This function filters out specified bad words from a given chat_message by replacing them with asterisks.
  • Regular Expression Pattern: A dynamic regex pattern is constructed based on the provided list of bad words.
  • Substitute Method – re.sub(): The re.sub() method replaces all instances of the pattern in the input string (chat_message) with asterisks.
    How can I add more bad words to filter?

    To include additional prohibited terms, update the bad_words list within the filter_bad_words function.

    Can I customize what replaces the filtered bad word?

    Yes, you can modify the replacement string within re.sub() as needed for customization.

    Is it case-sensitive when filtering out bad words?

    No, filtering is case-insensitive due to using flags=re.IGNORECASE.

    What if I have thousands of potential banned phrases?

    For extensive lists, consider storing them externally for easier management like in a file or database.

    Can this approach be used for real-time chat applications?

    While feasible, performance may vary based on factors such as message volume and word count per message.


    Efficiently filtering out inappropriate language from chat scripts plays a vital role in upholding a positive user experience. Leveraging Python’s powerful string manipulation capabilities coupled with regular expressions enables us to sanitize content effectively before presentation. Continuous updates to your list of prohibited terms enhance accuracy and user satisfaction.

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