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Lazy loading (also known as asynchronous loading) is a technique used in computer programming, especially web design and web development, to defer initialization of an object until it is needed. It can contribute to efficiency in the program's operation if properly and appropriately used.
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. It is a kind of lazy evaluation that refers specifically to the instantiation of objects or other resources.
A second significant side reaction in reactions of ketones and aldehydes is selanylation of the intermediate selenoxide. This process leads to elimination products retaining a carbon-selenium bond, [16] and is more difficult to prevent than the seleno-Pummerer reaction. Tertiary selenoxides, which are unable to undergo enolization, do not react ...
Selenium was originally developed by Jason Huggins in 2004 as an internal tool at ThoughtWorks. [5] Huggins was later joined by other programmers and testers at ThoughtWorks, before Paul Hammant joined the team and steered the development of the second mode of operation that would later become "Selenium Remote Control" (RC).
Lazy evaluation can also lead to reduction in memory footprint, since values are created when needed. [19] In practice, lazy evaluation may cause significant performance issues compared to eager evaluation. For example, on modern computer architectures, delaying a computation and performing it later is slower than performing it immediately.
Following rearrangement and loss of water, a second equivalent of water attacks the alpha position. Red amorphous selenium is liberated in the final step to give the 1,2-dicarbonyl product. [8] [9]: 4331 Allylic oxidation using selenium-dioxide proceeds via an ene reaction at the electrophilic selenium center.
In computer operating systems, demand paging (as opposed to anticipatory paging) is a method of virtual memory management. In a system that uses demand paging, the operating system copies a disk page into physical memory only when an attempt is made to access it and that page is not already in memory (i.e., if a page fault occurs).
Lazy learning methods are usually slower to evaluate. In practice, for very large databases with high concurrency loads, the queries are not postponed until actual query time, but recomputed in advance on a periodic basis - e.g., nightly, in anticipation of future queries, and the answers stored.