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py_echo_validator — Alphabetic Palindrome Check

Difficulty: easy

Write a function that checks if a string is a palindrome, ignoring spaces and case. Only alphabetic characters are considered for the comparison. An empty input (after filtering) is not a palindrome.

def echo_validator(text: str) -> bool:

Examples​

>>> echo_validator("racecar")
True

>>> echo_validator("A man a plan a canal Panama")
True

>>> echo_validator("race a car")
False

>>> echo_validator("Was it a car or a cat I saw")
True

>>> echo_validator("hello")
False

>>> echo_validator("Madam Im Adam")
True

>>> echo_validator("")
False

Solution​

Download py_echo_validator.py 
def echo_validator(text: str) -> bool:
    cleaned = [c.lower() for c in text if c.isalpha()]
    if not cleaned:
        return False
    return cleaned == cleaned[::-1]

How It Works​

Goal: Determine if the letters-only, case-folded version of the input reads the same forwards and backwards.

Approach: Filter to alphabetic characters, lowercase them, then compare the list to its reverse.

Step by step:

  1. Build a list of just the alphabetic characters, each lowercased.
  2. If the filtered list is empty, return False per the spec.
  3. Compare it to its reverse ([::-1]); equality means palindrome.

Key concept: Normalizing input before comparison — when "equal" means equal under some rule (case-insensitive, ignore punctuation), strip that variance away first so the core check stays simple.