Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

inline fun <T, R> Sequence<T>.foldIndexed(
    initial: R, 
    operation: (index: Int, acc: R, T) -> R
): R

Accumulates value starting with initial value and applying operation from left to right to current accumulator value and each element with its index in the original sequence.

Returns the specified initial value if the sequence is empty.

Parameters

operation -

function that takes the index of an element, current accumulator value and the element itself, and calculates the next accumulator value.

The operation is terminal.