Sorted

Sorted is an adjective describing a sequence or collection whose elements are arranged according to a defined order. Common orders are numeric ascending or descending and lexicographic (dictionary) order, but any criterion defined by a comparator may be used. A sorted sequence is easy to search and compare.

In computing, sorting arranges data to enable efficient operations such as binary search, merging, deduplication, and reporting. Sorting can be performed on lists, arrays, records, or streams. Sorting can be stable or unstable: stable sorts preserve the relative order of equal elements; unstable sorts may not.

Algorithms used to produce sorted data vary in speed and resource use. Efficient general-purpose sorts include quicksort, mergesort, and heapsort, typically averaging O(n log n) time. Some sorts, such as insertion sort or bubble sort, are simple but less scalable. Sorting may be in-place or require additional memory, and may be stable or unstable.

In programming languages, functions or methods named sort or sorted return data in a sorted order. For example, Python offers the built-in sorted(iterable, key=None, reverse=False) that returns a new list, and the list.sort() method that sorts the list in place; Java and C++ offer sort routines in standard libraries; many SQL dialects use ORDER BY to sort results. A key function or comparator can steer the sorting order, and reverse or descending options are common.

Applications include data preprocessing, database indexing, report generation, and streaming or external sorting where data exceeds memory.

See also: Sorting algorithm, Stable sort, Comparison sort.