Search results
Results From The WOW.Com Content Network
List comprehension is a syntactic construct available in some programming languages for creating a list based on existing lists. It follows the form of the mathematical set-builder notation (set comprehension) as distinct from the use of map and filter functions.
For example, to perform an element by element sum of two arrays, a and b to produce a third c, it is only necessary to write c = a + b In addition to support for vectorized arithmetic and relational operations, these languages also vectorize common mathematical functions such as sine.
A list may contain the same value more than once, and each occurrence is considered a distinct item. A singly-linked list structure, implementing a list with three integer elements. The term list is also used for several concrete data structures that can be used to implement abstract lists, especially linked lists and arrays.
In computer programming, lazy initialization is the tactic of delaying the creation of an object, the calculation of a value, or some other expensive process until the first time it is needed.
In Java associative arrays are implemented as "maps", which are part of the Java collections framework. Since J2SE 5.0 and the introduction of generics into Java, collections can have a type specified; for example, an associative array that maps strings to strings might be specified as follows:
C++'s std::vector and Rust's std::vec::Vec are implementations of dynamic arrays, as are the ArrayList [25] classes supplied with the Java API [26]: 236 and the .NET Framework. [27] [28]: 22 The generic List<> class supplied with version 2.0 of the .NET Framework is also implemented with dynamic arrays.
The Extended Array Library provides support for non-vector arrays. That is, arrays that have more than one dimension or arrays that have non-zero lower bounds. [1] The Extended Array Library doesn't add any extra types, but it does extend the array-handling mechanism. [2]
For example, in the Pascal programming language, the declaration type MyTable = array [1.. 4, 1.. 2] of integer, defines a new array data type called MyTable. The declaration var A: MyTable then defines a variable A of that type, which is an aggregate of eight elements, each being an integer variable identified by two indices.