runningFold
inline
fun
<
R
>
ShortArray
.
runningFold
(
initial
:
R
,
operation
:
(
acc
:
R
,
Short
)
->
R
)
:
List
<
R
>
(source)
inline
fun
<
R
>
FloatArray
.
runningFold
(
initial
:
R
,
operation
:
(
acc
:
R
,
Float
)
->
R
)
:
List
<
R
>
(source)
inline
fun
<
R
>
DoubleArray
.
runningFold
(
initial
:
R
,
operation
:
(
acc
:
R
,
Double
)
->
R
)
:
List
<
R
>
(source)
inline
fun
<
R
>
BooleanArray
.
runningFold
(
initial
:
R
,
operation
:
(
acc
:
R
,
Boolean
)
->
R
)
:
List
<
R
>
(source)
@ExperimentalUnsignedTypes
inline
fun
<
R
>
ULongArray
.
runningFold
(
initial
:
R
,
operation
:
(
acc
:
R
,
ULong
)
->
R
)
:
List
<
R
>
(source)
@ExperimentalUnsignedTypes
inline
fun
<
R
>
UByteArray
.
runningFold
(
initial
:
R
,
operation
:
(
acc
:
R
,
UByte
)
->
R
)
:
List
<
R
>
(source)
@ExperimentalUnsignedTypes
inline
fun
<
R
>
UShortArray
.
runningFold
(
initial
:
R
,
operation
:
(
acc
:
R
,
UShort
)
->
R
)
:
List
<
R
>
(source)
Returns a list containing successive accumulation values generated by applying operation from left to right to each element and current accumulator value that starts with initial value.
Note that
acc
value passed to
operation
function should not be mutated;
otherwise it would affect the previous value in resulting list.
import kotlin.test.*
fun main(args: Array<String>) {
//sampleStart
val strings = listOf("a", "b", "c", "d")
println(strings.runningFold("s") { acc, string -> acc + string }) // [s, sa, sab, sabc, sabcd]
println(strings.runningFoldIndexed("s") { index, acc, string -> acc + string + index }) // [s, sa0, sa0b1, sa0b1c2, sa0b1c2d3]
println(emptyList<String>().runningFold("s") { _, _ -> "X" }) // [s]
//sampleEnd
}
Parameters
operation
- function that takes current accumulator value and an element, and calculates the next accumulator value.