What causes "The grid does not contain the appropriate information" in TheAlgorithms/Python?

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.

TheAlgorithms/Python · error · TypeError

The grid does not contain the appropriate information

Error message

The grid does not contain the appropriate information

What it means

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.

Source

Thrown at graphs/minimum_path_sum.py:33

    ...     [4, 4, 4, 5, 1],
    ...     [9, 6, 3, 1, 0],
    ...     [8, 4, 3, 2, 7],
    ... ])
    20

    >>> min_path_sum(None)
    Traceback (most recent call last):
        ...
    TypeError: The grid does not contain the appropriate information

    >>> min_path_sum([[]])
    Traceback (most recent call last):
        ...
    TypeError: The grid does not contain the appropriate information
    """

    if not grid or not grid[0]:
        raise TypeError("The grid does not contain the appropriate information")

    for cell_n in range(1, len(grid[0])):
        grid[0][cell_n] += grid[0][cell_n - 1]
    row_above = grid[0]

    for row_n in range(1, len(grid)):
        current_row = grid[row_n]
        grid[row_n] = fill_row(current_row, row_above)
        row_above = grid[row_n]

    return grid[-1][-1]


def fill_row(current_row: list, row_above: list) -> list:
    """
    >>> fill_row([2, 2, 2], [1, 2, 3])
    [3, 4, 5]
    """

View on GitHub (pinned to f5988cc097)

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.

Example fix

# before
best = min_path_sum(parse_grid(path))  # parse_grid may return []

# after
grid = parse_grid(path)
if not grid or not grid[0]:
    raise ValueError(f"empty grid from {path}")
best = min_path_sum(grid)

Defensive patterns

Strategy: type-guard

Validate before calling

def is_valid_grid(grid: list[list[int]] | None) -> bool:
    return bool(grid) and bool(grid[0]) and all(len(row) == len(grid[0]) for row in grid)

Type guard

from typing import Optional

def is_parseable_grid(grid: object) -> bool:
    return (
        isinstance(grid, list)
        and len(grid) > 0
        and isinstance(grid[0], list)
        and len(grid[0]) > 0
    )

Try / catch

try:
    best = min_path_sum(grid)
except TypeError:
    best = None  # or raise a domain-specific 'empty input' error with the source path

Prevention

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.

When it happens

Trigger: 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.

Common situations: 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.

Related errors

AI-assisted analysis of TheAlgorithms/Python@f5988cc097 (2026-08-14). Data as JSON: /api/errors/f4d77e7410f27fff. Report an issue: GitHub.