{"record":{"id":"8f13b398dd222bb9","repo":"TheAlgorithms/Python","slug":"that-number-is-larger-than-our-acceptable-range","errorCode":null,"errorMessage":"That number is larger than our acceptable range.","messagePattern":"That number is larger than our acceptable range\\.","errorType":"validation","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"project_euler/problem_004/sol1.py","lineNumber":47,"sourceCode":"        ...\n    ValueError: That number is larger than our acceptable range.\n    \"\"\"\n\n    # fetches the next number\n    for number in range(n - 1, 9999, -1):\n        str_number = str(number)\n\n        # checks whether 'str_number' is a palindrome.\n        if str_number == str_number[::-1]:\n            divisor = 999\n\n            # if 'number' is a product of two 3-digit numbers\n            # then number is the answer otherwise fetch next number.\n            while divisor != 99:\n                if (number % divisor == 0) and (len(str(number // divisor)) == 3.0):\n                    return number\n                divisor -= 1\n    raise ValueError(\"That number is larger than our acceptable range.\")\n\n\nif __name__ == \"__main__\":\n    print(f\"{solution() = }\")\n","sourceCodeStart":29,"sourceCodeEnd":52,"githubUrl":"https://github.com/TheAlgorithms/Python/blob/f5988cc09713315817df6a7e327e258013a94440/project_euler/problem_004/sol1.py#L29-L52","documentation":"Raised by project_euler/problem_004/sol1.py:solution(n=998001) when the downward scan from n-1 to 10000 finds no palindromic number that is a product of two 3-digit numbers. The smallest such palindrome is 101*101 = 10201, so any n <= 10201 exhausts the loop and raises. The message ('That number is larger than our acceptable range') is misleading - it actually means n is too SMALL, not too large.","triggerScenarios":"solution(10000) (per the doctest), or any n <= 10201 such as solution(0) or solution(10201). Note solution(10201) itself raises because the range starts at n-1 exclusive of a match at exactly 10201 only if it divides out - the safe minimum is n > 10201.","commonSituations":"Parameterized sweeps over n that start too low; misreading the message and raising the bound (the opposite of the fix); unit tests generated from the doctest that re-use solution(10000) expecting failure; changing the default 998001 (999*999) to a smaller limit while testing.","solutions":["Call with n > 10201 (the smallest 3-digit-product palindrome plus one); the default 998001 works.","Read the error correctly: it means 'no answer exists at or below n', so increase n - do not decrease it.","Catch ValueError when sweeping n values and treat it as 'no palindrome in range'.","Optionally patch the message locally to 'No palindromic product of two 3-digit numbers exists below n' to reduce confusion."],"exampleFix":"# before\nprint(solution(10000))  # ValueError: That number is larger than our acceptable range.\n\n# after\ntry:\n    print(solution(n))\nexcept ValueError:\n    print(f'no 3-digit palindrome product below {n}; need n > 10201')","handlingStrategy":"validation","validationCode":"MIN_N = 10201 + 1  # smallest palindrome product of two 3-digit numbers, plus 1\nif n <= MIN_N:\n    raise ValueError(f'n must be > 10201 for a 3-digit palindrome product, got {n}')\nsolution(n)","typeGuard":"def has_palindrome_in_range(n: int) -> bool:\n    return isinstance(n, int) and n > 10201","tryCatchPattern":"try:\n    solution(n)\nexcept ValueError as e:\n    if 'acceptable range' in str(e):\n        # means n too small, despite the message wording\n        ...","preventionTips":["Remember the message is inverted: it fires when n is too SMALL.","Keep n above 10201 (101*101); the default 998001 is safe.","When sweeping n, catch this ValueError as 'no answer below n'."],"tags":["python-euler","palindrome","valueerror","misleading-message","range-check"],"backgroundTag":null,"analyzedSha":"f5988cc09713315817df6a7e327e258013a94440","analyzedAt":"2026-08-14T17:30:07.041Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}