Python: Check if a given function returns True for at least one element in the list

Last update on April 19 2025 12:57:44 (UTC/GMT +8 hours)

Check Any True in List

Write a Python program to check if a given function returns True for at least one element in the list.

Use all() and fn to check if fn returns False for all the elements in the list.

Sample Solution:

Python Code:

# Define a function named 'test' that checks whether a condition is False for all elements in a list.
def test(lst, fn=lambda x: x):
    return all(not fn(x) for x in lst)
    # The 'all' function checks if the given condition 'not fn(x)' is False for all elements in the list 'lst'.

# Test the 'test' function with different lists and conditions.
print(test([1, 0, 2, 3], lambda x: x >= 3))
# Check if all elements are less than 3. (Expected output: False)

print(test([1, 0, 2, 3], lambda x: x < 0))
# Check if all elements are less than 0. (Expected output: False)

print(test([2, 2, 4, 4]))
# Check if all elements are False (considering default condition of 'x').
# Since there are no False elements, the expected output is True.

Sample Output:

False
True
False

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python program to check if at least one element in a list satisfies a custom predicate and return its index.
Write a Python program to verify if any element in a list meets a condition and then output that element along with a boolean flag.
Write a Python program to scan a list and return True immediately upon finding an element that passes a provided test function.
Write a Python program to test if any string in a list contains a specific character and output the first matching string.

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