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Elements can be removed from the end of a dynamic array in constant time, as no resizing is required. The number of elements used by the dynamic array contents is its logical size or size, while the size of the underlying array is called the dynamic array's capacity or physical size, which is the maximum possible size without relocating data. [2]
In other array types, a slice can be replaced by an array of different size, with subsequent elements being renumbered accordingly – as in Python's list assignment "A[5:5] = [10,20,30]", that inserts three new elements (10, 20, and 30) before element "A[5]".
In computer science, an array is a data structure consisting of a collection of elements (values or variables), of same memory size, each identified by at least one array index or key. An array is stored such that the position of each element can be computed from its index tuple by a mathematical formula.
The following list contains syntax examples of how to determine the dimensions (index of the first element, the last element or the size in elements). Some languages index from zero. Some index from one. Some carry no such restriction, or even allow indexing by any enumerated type, not only integers.
Note how the use of A[i][j] with multi-step indexing as in C, as opposed to a neutral notation like A(i,j) as in Fortran, almost inevitably implies row-major order for syntactic reasons, so to speak, because it can be rewritten as (A[i])[j], and the A[i] row part can even be assigned to an intermediate variable that is then indexed in a separate expression.
sizeof can be used to determine the number of elements in an array, by dividing the size of the entire array by the size of a single element. This should be used with caution; When passing an array to another function, it will "decay" to a pointer type. At this point, sizeof will return the size of the pointer, not the total size of the array.
A[-1, *] % The last row of A A[[1:5], [2:7]] % 2d array using rows 1-5 and columns 2-7 A[[5:1:-1], [2:7]] % Same as above except the rows are reversed Array indices can also be arrays of integers. For example, suppose that I = [0:9] is an array of 10 integers.
The sizeof operator on such a struct gives the size of the structure as if the flexible array member were empty. This may include padding added to accommodate the flexible member; the compiler is also free to re-use such padding as part of the array itself. [2]