Added aggregate operations
This commit is contained in:
Anirban Chatterjee
parent
6aa7c57db6
commit
f44cc311bd
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package com.baeldung.kotlin.collections
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class AggregateOperations {
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private val numbers = listOf(1, 15, 3, 8)
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fun countList(): Int {
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return numbers.count()
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}
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fun sumList(): Int {
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return numbers.sum()
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}
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fun averageList(): Double {
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return numbers.average()
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}
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fun maximumInList(): Int? {
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return numbers.max()
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}
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fun minimumInList(): Int? {
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return numbers.min()
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}
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fun maximumByList(): Int? {
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return numbers.maxBy { it % 5 }
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}
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fun minimumByList(): Int? {
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return numbers.minBy { it % 5 }
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}
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fun maximumWithList(): String? {
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val strings = listOf("Berlin", "Kolkata", "Prague", "Barcelona")
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return strings.maxWith(compareBy { it.length % 4 })
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}
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fun minimumWithList(): String? {
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val strings = listOf("Berlin", "Kolkata", "Prague", "Barcelona")
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return strings.minWith(compareBy { it.length % 4 })
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}
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fun sumByList(): Int {
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return numbers.sumBy { it * 5 }
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}
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fun sumByDoubleList(): Double {
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return numbers.sumByDouble { it.toDouble() / 8 }
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}
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fun foldList(): Int {
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println("fold operation")
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val result = numbers.fold(100) { total, it ->
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println("total = $total, it = $it")
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total - it
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}
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println(result) // ((((100 - 1)-15)-3)-8) = 73
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return result
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}
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fun foldRightList(): Int {
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println("foldRight operation")
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val result = numbers.foldRight(100) { it, total ->
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println("total = $total, it = $it")
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total - it
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}
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println(result) // ((((100-8)-3)-15)-1) = 73
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return result
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}
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fun foldIndexedList(): Int {
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println("foldIndexed operation")
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val result = numbers.foldIndexed(100) { index, total, it ->
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println("total = $total, it = $it, index = $index")
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if (index.minus(2) >= 0) total - it else total
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}
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println(result) // ((100 - 3)-8) = 89
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return result
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}
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fun foldRightIndexedList(): Int {
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println("foldRightIndexed operation")
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val result = numbers.foldRightIndexed(100) { index, it, total ->
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println("total = $total, it = $it, index = $index")
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if (index.minus(2) >= 0) total - it else total
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}
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println(result) // ((100 - 8)-3) = 89
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return result
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}
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fun reduceList(): Int {
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println("reduce operation")
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val result = numbers.reduce { total, it ->
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println("total = $total, it = $it")
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total - it
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}
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println(result) // (((1 - 15)-3)-8) = -25
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return result
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}
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fun reduceRightList(): Int {
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println("reduceRight operation")
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val result = numbers.reduceRight() { it, total ->
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println("total = $total, it = $it")
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total - it
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}
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println(result) // ((8-3)-15)-1) = -11
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return result
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}
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fun reduceIndexedList(): Int {
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println("reduceIndexed operation")
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val result = numbers.reduceIndexed { index, total, it ->
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println("total = $total, it = $it, index = $index")
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if (index.minus(2) >= 0) total - it else total
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}
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println(result) // ((1-3)-8) = -10
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return result
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}
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fun reduceRightIndexedList(): Int {
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println("reduceRightIndexed operation")
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val result = numbers.reduceRightIndexed { index, it, total ->
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println("total = $total, it = $it, index = $index")
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if (index.minus(2) >= 0) total - it else total
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}
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println(result) // ((8-3) = 5
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return result
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}
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}
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@ -0,0 +1,104 @@
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package com.baeldung.kotlin.collections
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import org.junit.jupiter.api.Test
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import kotlin.test.assertEquals
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class AggregateOperationsUnitTest {
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private val classUnderTest: AggregateOperations = AggregateOperations()
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@Test
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fun whenCountOfList_thenReturnsValue() {
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assertEquals(4, classUnderTest.countList())
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}
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@Test
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fun whenSumOfList_thenReturnsTotalValue() {
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assertEquals(27, classUnderTest.sumList())
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}
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@Test
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fun whenAverageOfList_thenReturnsValue() {
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assertEquals(6.75, classUnderTest.averageList())
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}
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@Test
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fun whenMaximumOfList_thenReturnsMaximumValue() {
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assertEquals(15, classUnderTest.maximumInList())
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}
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@Test
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fun whenMinimumOfList_thenReturnsMinimumValue() {
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assertEquals(1, classUnderTest.minimumInList())
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}
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@Test
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fun whenMaxByList_thenReturnsLargestValue() {
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assertEquals(3, classUnderTest.maximumByList())
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}
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@Test
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fun whenMinByList_thenReturnsSmallestValue() {
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assertEquals(15, classUnderTest.minimumByList())
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}
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@Test
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fun whenMaxWithList_thenReturnsLargestValue(){
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assertEquals("Kolkata", classUnderTest.maximumWithList())
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}
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@Test
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fun whenMinWithList_thenReturnsSmallestValue(){
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assertEquals("Barcelona", classUnderTest.minimumWithList())
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}
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@Test
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fun whenSumByList_thenReturnsIntegerValue(){
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assertEquals(135, classUnderTest.sumByList())
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}
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@Test
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fun whenSumByDoubleList_thenReturnsDoubleValue(){
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assertEquals(3.375, classUnderTest.sumByDoubleList())
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}
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@Test
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fun whenFoldList_thenReturnsValue(){
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assertEquals(73, classUnderTest.foldList())
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}
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@Test
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fun whenFoldRightList_thenReturnsValue(){
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assertEquals(73, classUnderTest.foldRightList())
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}
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@Test
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fun whenFoldIndexedList_thenReturnsValue(){
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assertEquals(89, classUnderTest.foldIndexedList())
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}
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@Test
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fun whenFoldRightIndexedList_thenReturnsValue(){
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assertEquals(89, classUnderTest.foldRightIndexedList())
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}
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@Test
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fun whenReduceList_thenReturnsValue(){
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assertEquals(-25, classUnderTest.reduceList())
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}
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@Test
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fun whenReduceRightList_thenReturnsValue(){
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assertEquals(-11, classUnderTest.reduceRightList())
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}
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@Test
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fun whenReduceIndexedList_thenReturnsValue(){
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assertEquals(-10, classUnderTest.reduceIndexedList())
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}
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@Test
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fun whenReduceRightIndexedList_thenReturnsValue(){
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assertEquals(5, classUnderTest.reduceRightIndexedList())
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}
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}
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