Three-Dimensional Arrays, Records and Tuples

A one-dimensional array can store scores for students; a two-dimensional array can use student and test coordinates. Add a third coordinate for term to obtain scores[term,student,test] under an agreed order. A dimension’s length is a count, not its final zero-based index. Lengths 2,3,4 therefore allow term 0–1, student 0–2 and test 0–3.

The array contains 2×3×4=24 positions. Traversing all values needs a loop over each dimension, with bounds derived from their lengths. A correct loop can still report the wrong interpretation if term and student are swapped. Document coordinate order and use a small distinctive test value at a known position to check it.

A record groups related named attributes, such as StudentID, Name and Active. The fields can have different types because their meanings differ. A list stores an ordered sequence and often provides dynamic operations such as insertion; an array model may instead have a declared fixed size and homogeneous element type. Language implementations vary, so follow the model stated.

A tuple is an ordered collection whose positions have meaning; Python tuples are immutable sequences. Immutability means the tuple’s own element bindings cannot be reassigned, not that every object referred to by a tuple is recursively immutable. A tuple containing a list can still refer to a list that changes. Choose named records when anonymous position numbers would obscure the data model.

Python nested lists can model a three-dimensional collection, but they are not automatically a contiguous fixed-size array. In the example, each comprehension creates a separate inner list for its row. Assigning grid[1][2][3]=9 should change only that intended position. Repeating the same mutable row reference can make several apparent rows change together.

Test construction as well as access: check lengths at each level, the total number of cells and that a write does not affect another row or plane. Validate coordinates before using untrusted input as indices. Python negative indices have their own language meaning; they should not silently be accepted as valid coordinates in a zero-to-length-minus-one application contract.

grid = [[[0 for test in range(4)]
         for student in range(3)]
        for term in range(2)]
grid[1][2][3] = 9
print(grid[1][2][3], grid[0][2][3], grid[1][0][3])
print(sum(len(row) for plane in grid for row in plane))
entry = (17, "Amina", True)
print(entry[1])

Attempt the task before opening its worked response. Record each change of state, explain the rule used, and check the result against the original requirements. Code examples labelled Python 3 use that language’s conventions; pseudocode states its own assumptions.