Python function to filter strings with a specific substring

Last update on March 31 2025 12:56:09 (UTC/GMT +8 hours)

9. Substring Excluder

Write a Python function that filters out elements from a list of strings containing a specific substring using the filter function.

Sample Solution:

Python Code:

def filter_strings_with_substring(strings, substring):
    """
    Filters out elements from a list of strings containing a specific substring.

    Args:
        strings (list): A list of strings.
        substring (str): The substring to search for in the strings.

    Returns:
        list: A new list containing only the strings that contain the substring.
    """
    # Define the filtering function
    def contains_substring(string):
        return substring in string

    # Use the filter function to filter out strings with the substring
    filtered_strings = list(filter(contains_substring, strings))

    return filtered_strings

# Example usage:
strings = ["Red", "Green", "Orange", "White", "Black", "Pink", "Yellow"]
print("List of words:")
print(strings)
substring = "l"
print("Substring:",substring)
print("Filter out strings with the substring:")
result = filter_strings_with_substring(strings, substring)
print(result)  

Explanation:

In the exercise above -

• First, the "filter_strings_with_substring()" function takes two arguments: strings (a list of strings) and substring (the substring to search for).
• Inside the function, we define a nested function "contains_substring()" that checks if a string contains the specified substring using the in operator.
• Use the filter function to filter out strings from the strings list by applying the "contains_substring()" function as the filtering condition.
• Finally, the filtered strings containing the specified substring are converted to a list and returned as the result.

Sample Output:

List of words:
['Red', 'Green', 'Orange', 'White', 'Black', 'Pink', 'Yellow']
Substring: l
Filter out strings with the substring:
['Black', 'Yellow']

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to filter out strings containing a specific substring and then return the remaining strings sorted by their lengths.
• Write a Python function that uses the filter function to remove strings containing a given substring and then converts the remaining strings to lowercase.
• Write a Python program to filter a list of strings to exclude those with a specific substring, and then concatenate the remaining strings with a space separator.
• Write a Python function that filters a list of strings, retaining only those that do not contain a given substring, and then counts the number of retained strings.

Python Code Editor:

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