Droplast

Droplast is not a single, universally defined term. In practice, it commonly refers to an operation that removes elements from the end of a sequence. The exact name and syntax vary by language or library, with common variants including dropLast, dropRight, and drop_last.

In Kotlin and other similar languages, the operation is typically called dropLast. For example, a list.dropLast(n) returns a new list containing all elements except the last n; if n is 1, the last element is removed. In Scala, the equivalent function is dropRight(n), which yields the same end-offset effect.

In JavaScript, libraries such as Lodash provide dropRight(array, [n=1]), which returns a new array with the last n elements removed. Many functional languages offer a closely related concept, often implemented as dropRight, takeRight, or init (the latter referring to removing the last element in some contexts).

In Python, there is no built-in function named dropLast, but the same result is achieved via slicing, for example lst[:-n] for n > 0. The concept can also be implemented via library helpers in various ecosystems.

Performance considerations vary by implementation. Dropping elements typically involves creating a new collection and copying elements, resulting in O(n) time complexity and O(n) additional space, where n is the number of elements in the output or the number of elements removed, depending on the approach.

If used outside programming, droplast may be encountered as shorthand for a “drop last elements” operation. The term’s exact meaning thus depends on context and the language or library in use.

See also: drop, dropRight, dropLast, takeLast, init.