Append

Append is a verb meaning to attach something to the end of something else. It derives from the Latin appendere, to hang upon, and is closely related to the noun appendix, a thing added at the end.

In writing and publishing, to append means to attach supplementary material at the end of a document. A common instance is an appendix, which collects additional information, data, or references.

In computing, append describes adding an item to the end of a sequence or file. In programming, operations named append add an element to the end of a list or array (for example, list.append(x) in Python). Strings may be appended by concatenation or through language- or library-specific APIs, though many languages treat strings as immutable and create a new string rather than modifying the original in place.

In file I/O, append mode allows writing to the end of a file without overwriting existing content. Commands and APIs that support appending include shell redirection using >>, or APIs that provide append methods on streams or writers.

In data processing, appending is used to combine datasets by adding rows or records to the end of an existing set. Some libraries deprecate explicit append in favor of general concatenation, such as concatenating data structures. In databases, appending is done through insert operations that add new rows to a table.

See also: prepend, concatenate, insert.