Python function to filter numbers by threshold

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

3. Threshold Filter

Write a Python function that filters out all elements less than or equal than a specified value from a list of numbers using the filter function.

Sample Solution:

Python Code:

def filter_numbers_less_than(numbers, threshold):
    """
    Filters out all elements less than or equal to a specified value from a list of numbers.

    Args:
        numbers (list): A list of numbers.
        threshold (float): The threshold value to compare against.

    Returns:
        list: A new list containing only the numbers less than or equal to the threshold.
    """
    # Define the filtering function
    def is_less_than_threshold(num):
        return num <= threshold

    # Use the filter function to filter out numbers
    filtered_numbers = list(filter(is_less_than_threshold, numbers))

    return filtered_numbers

# Example usage:
numbers = [20, 15, 24, 37, 23, 11, 7]
print("Original list of numbers:",numbers)
threshold = 20
print("\nFilters out all elements less than or equal to a specified value",threshold,":")
result = filter_numbers_less_than(numbers, threshold)
print(result)

Explanation:

In the exercise above -

• The "filter_numbers_less_than()" function takes two arguments: numbers (a list of numbers) and a threshold (the value to compare against).
• Inside the function, we define a nested function "is_less_than_threshold()" that checks if a number is greater than or equal to the specified threshold.
• We use the filter function to filter out numbers from the numbers list by applying the "is_less_than_threshold()" function as the filtering condition.
• The filtered numbers are converted to a list and returned as the result.

Sample Output:

Original list of numbers: [20, 15, 24, 37, 23, 11, 7]

Filters out all elements less than or equal to a specified value 20 :
[20, 15, 11, 7]

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python function that takes a threshold value and filters out all elements in a list that are less than or equal to that threshold, then multiplies the remaining numbers by 2.
• Write a Python program that computes the average of a list and uses the filter function to remove all numbers less than or equal to this average.
• Write a Python function that uses filter to remove elements less than or equal to a specified value and then maps the remaining numbers to their natural logarithms.
• Write a Python program that prompts the user for a threshold value, filters out numbers from a list that do not exceed it, and then returns a sorted list of the remaining elements.

Python Code Editor:

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