Python: Find the value of the last element in the given list that satisfies the provided testing function

Last update on April 19 2025 12:57:53 (UTC/GMT +8 hours)

Last Value Satisfying Function

Write a Python program to find the value of the last element in the given list that satisfies the provided testing function.

Use a list comprehension and next() to return the last element in lst for which fn returns True.

Sample Solution:

Python Code:

# Define a function 'find_last' that takes a list 'lst' and a function 'fn' as input.
def find_last(lst, fn):
    # Use a generator expression to find the last element 'x' in the reversed list 'lst[::-1]'
    # for which 'fn(x)' is true. The 'next' function is used to retrieve the last matching element.
    return next(x for x in lst[::-1] if fn(x))

# Call the 'find_last' function with a list and a lambda function to find the last odd number in the list.
# Print the result.
print(find_last([1, 2, 3, 4], lambda n: n % 2 == 1))
# Call the 'find_last' function again with a lambda function to find the last even number in the list.
# Print the result.
print(find_last([1, 2, 3, 4], lambda n: n % 2 == 0))

Sample Output:

3
4

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python program to find the last value in a list that satisfies a given predicate, returning a default value if none qualify.
Write a Python program to retrieve the last even number in a list using a provided testing function.
Write a Python program to find the last value in a list that meets a condition defined by a lambda function and output its index along with the value.
Write a Python program to determine the last value in a list that, when processed by a function, results in a number greater than a specified threshold.

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