Array
Array is a term that applies to programming. Array denotes a series of objects that are of the same size and type.
These objects can be numerical (an integer or a floating-point, an integer with a decimal point) or alphabetical. Each of these objects can be called an array element. The location of an item in an array is called the array index. An array index is generally written as A[i,j,k], where A is the name of the array and i, j, and k are the subsets of the array. In the C programming language, the array index is written as A[i][j]k].
An array has two important characteristics. First, each element has the same data type, even though they may have different values. In other words, an array of integers consists entirely of integers, although the value of the integers may differ. Second, the entire array is stored contiguously--the sectors the memory occupies are immediately adjacent to one another, with no intervening gaps. Languages differ as to the pattern of storage. For example, in a two-dimensional array, each row can be stored contiguously in some languages while each column is stored contiguously in another language.
There are several types of arrays. An associative array is an array in which the items can be accessed by the use of a field designed to sort the data. A dynamic array is an array whose size can change over time. Items may be added or removed, and the amount of memory used may also change.
Some arrays have more than one dimension. The number of dimensions in an array depends on the language, but is usually unlimited. A single variable, such as a character or a single number, is also called a scalar, and can be considered as a zero-dimensional array. A one-dimensional array, such as text, is called a vector. A two-dimensional array, such as the rows and columns of a spreadsheet, is called a matrix.
The array format has practical significance. Users that generate a large volume of data, such as scientific experimentation, require a way to organize the data such that it can be meaningfully and practically analyzed. Often, as well, the data is not examined sequentially, but rather in an unpredictable order as the analysis dictates. Arrays are suited to this unpredictable order of data access. Languages such as C and FORTRAN have accomplished the organization of large volumes of data by arranging the bank of data into subsets. Each of these subsets is an array. By having each subset comprised of the same type of information, a program can be written to analyze each subset.
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