{"record":{"id":"f4d77e7410f27fff","repo":"TheAlgorithms/Python","slug":"the-grid-does-not-contain-the-appropriate-informat","errorCode":null,"errorMessage":"The grid does not contain the appropriate information","messagePattern":"The grid does not contain the appropriate information","errorType":"exception","errorClass":"TypeError","httpStatus":null,"severity":"error","filePath":"graphs/minimum_path_sum.py","lineNumber":33,"sourceCode":"    ...     [4, 4, 4, 5, 1],\n    ...     [9, 6, 3, 1, 0],\n    ...     [8, 4, 3, 2, 7],\n    ... ])\n    20\n\n    >>> min_path_sum(None)\n    Traceback (most recent call last):\n        ...\n    TypeError: The grid does not contain the appropriate information\n\n    >>> min_path_sum([[]])\n    Traceback (most recent call last):\n        ...\n    TypeError: The grid does not contain the appropriate information\n    \"\"\"\n\n    if not grid or not grid[0]:\n        raise TypeError(\"The grid does not contain the appropriate information\")\n\n    for cell_n in range(1, len(grid[0])):\n        grid[0][cell_n] += grid[0][cell_n - 1]\n    row_above = grid[0]\n\n    for row_n in range(1, len(grid)):\n        current_row = grid[row_n]\n        grid[row_n] = fill_row(current_row, row_above)\n        row_above = grid[row_n]\n\n    return grid[-1][-1]\n\n\ndef fill_row(current_row: list, row_above: list) -> list:\n    \"\"\"\n    >>> fill_row([2, 2, 2], [1, 2, 3])\n    [3, 4, 5]\n    \"\"\"","sourceCodeStart":15,"sourceCodeEnd":51,"githubUrl":"https://github.com/TheAlgorithms/Python/blob/f5988cc09713315817df6a7e327e258013a94440/graphs/minimum_path_sum.py#L15-L51","documentation":"Thrown by min_path_sum() when the input grid carries no usable data: grid is None/empty, or the first row is empty (not grid or not grid[0]). The dynamic-programming sweep over rows and columns cannot even initialize its first-row prefix sums without at least one cell, so the function raises TypeError instead of returning a bogus sum.","triggerScenarios":"Calling min_path_sum(None), min_path_sum([]), or min_path_sum([[]]). Also triggered when a grid parser returns an empty list for a blank input file or when a 0-column matrix (rows of length 0) is passed.","commonSituations":"Reading a grid from a file/CSV that is empty or has headers only; upstream code that returns [] on parse failure instead of raising; test fixtures with empty edge-case grids.","solutions":["Check the grid is non-empty and every row is non-empty before calling: if not grid or not grid[0]: handle the empty case in your code.","Fix the data source so it produces at least one row and one column.","Treat empty input as 0/None at the caller boundary instead of forwarding it to min_path_sum."],"exampleFix":"# before\nbest = min_path_sum(parse_grid(path))  # parse_grid may return []\n\n# after\ngrid = parse_grid(path)\nif not grid or not grid[0]:\n    raise ValueError(f\"empty grid from {path}\")\nbest = min_path_sum(grid)","handlingStrategy":"type-guard","validationCode":"def is_valid_grid(grid: list[list[int]] | None) -> bool:\n    return bool(grid) and bool(grid[0]) and all(len(row) == len(grid[0]) for row in grid)","typeGuard":"from typing import Optional\n\ndef is_parseable_grid(grid: object) -> bool:\n    return (\n        isinstance(grid, list)\n        and len(grid) > 0\n        and isinstance(grid[0], list)\n        and len(grid[0]) > 0\n    )","tryCatchPattern":"try:\n    best = min_path_sum(grid)\nexcept TypeError:\n    best = None  # or raise a domain-specific 'empty input' error with the source path","preventionTips":["Validate grids at the parse boundary (file/CSV reader), not at the algorithm call.","Return or raise a sentinel from the parser for empty files instead of an empty list.","Include empty-grid fixtures in tests so the contract stays explicit."],"tags":["dynamic-programming","grid","validation","type-guard"],"backgroundTag":null,"analyzedSha":"f5988cc09713315817df6a7e327e258013a94440","analyzedAt":"2026-08-14T17:30:07.041Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}