fixed describe and tests

Author: Jolanrensen

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/map.kt

@@ -31,10 +31,7 @@ public inline fun <C, reified R> ColumnReference<C>.map(
 
 // region DataColumn
 
-public inline fun <T, reified R> DataColumn<T>.map(
-    infer: Infer = Infer.Nulls,
-    crossinline transform: (T) -> R,
-): DataColumn<R> {
+public inline fun <T, reified R> DataColumn<T>.map(infer: Infer = Infer.Nulls, transform: (T) -> R): DataColumn<R> {
     val newValues = Array(size()) { transform(get(it)) }.asList()
     return DataColumn.createByType(name(), newValues, typeOf<R>(), infer)
 }

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/typeConversions.kt

@@ -83,11 +83,17 @@ public fun DataColumn<Any>.asNumbers(): ValueColumn<Number> {
     return this as ValueColumn<Number>
 }
 
-public fun <T> DataColumn<T>.asComparable(): DataColumn<Comparable<T>> {
+public fun <T : Any> DataColumn<T>.asComparable(): DataColumn<Comparable<T>> {
     require(valuesAreComparable())
     return this as DataColumn<Comparable<T>>
 }
 
+@JvmName("asComparableNullable")
+public fun <T : Any?> DataColumn<T?>.asComparable(): DataColumn<Comparable<T>?> {
+    require(valuesAreComparable())
+    return this as DataColumn<Comparable<T>?>
+}
+
 public fun <T> ColumnReference<T?>.castToNotNullable(): ColumnReference<T> = cast()
 
 public fun <T> DataColumn<T?>.castToNotNullable(): DataColumn<T> {

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/api/describe.kt

@@ -13,7 +13,6 @@ import org.jetbrains.kotlinx.dataframe.api.asNumbers
 import org.jetbrains.kotlinx.dataframe.api.cast
 import org.jetbrains.kotlinx.dataframe.api.concat
 import org.jetbrains.kotlinx.dataframe.api.isNumber
-import org.jetbrains.kotlinx.dataframe.api.isPrimitiveNumber
 import org.jetbrains.kotlinx.dataframe.api.map
 import org.jetbrains.kotlinx.dataframe.api.maxOrNull
 import org.jetbrains.kotlinx.dataframe.api.mean
@@ -30,6 +29,7 @@ import org.jetbrains.kotlinx.dataframe.columns.size
 import org.jetbrains.kotlinx.dataframe.columns.values
 import org.jetbrains.kotlinx.dataframe.impl.columns.addPath
 import org.jetbrains.kotlinx.dataframe.impl.columns.asAnyFrameColumn
+import org.jetbrains.kotlinx.dataframe.impl.isPrimitiveNumber
 import org.jetbrains.kotlinx.dataframe.impl.renderType
 import org.jetbrains.kotlinx.dataframe.index
 import org.jetbrains.kotlinx.dataframe.kind
@@ -38,7 +38,7 @@ import org.jetbrains.kotlinx.dataframe.type
 internal fun describeImpl(cols: List<AnyCol>): DataFrame<ColumnDescription> {
     val allCols = cols.collectAll(false)
 
-    val hasNumericCols = allCols.any { it.isPrimitiveNumber() }
+    val hasNumericCols = allCols.any { it.isNumber() }
     val hasComparableCols = allCols.any { it.valuesAreComparable() }
     val hasLongPaths = allCols.any { it.path().size > 1 }
     var df = allCols.toDataFrame {
@@ -56,8 +56,8 @@ internal fun describeImpl(cols: List<AnyCol>): DataFrame<ColumnDescription> {
                 ?.key
         }
         if (hasNumericCols) {
-            ColumnDescription::mean from { if (it.isPrimitiveNumber()) it.asNumbers().mean() else null }
-            ColumnDescription::std from { if (it.isPrimitiveNumber()) it.asNumbers().std() else null }
+            ColumnDescription::mean from { if (it.isNumber()) it.asNumbers().mean() else null }
+            ColumnDescription::std from { if (it.isNumber()) it.asNumbers().std() else null }
         }
         if (hasComparableCols || hasNumericCols) {
             ColumnDescription::min from inferType {
@@ -111,12 +111,20 @@ private fun List<AnyCol>.collectAll(atAnyDepth: Boolean): List<AnyCol> =
     }
 
 /** Converts a column to a comparable column if it is not already comparable. */
-private fun DataColumn<Any?>.convertToComparableOrNull(): DataColumn<Comparable<Any?>>? =
-    when {
+@Suppress("UNCHECKED_CAST")
+private fun DataColumn<Any?>.convertToComparableOrNull(): DataColumn<Comparable<Any>?>? {
+    return when {
         valuesAreComparable() -> asComparable()
 
         // Found incomparable number types, convert all to Double first
-        isPrimitiveNumber() -> map { (it as Number?)?.toDouble() }.cast()
+        isNumber() -> cast<Number?>().map {
+            if (it?.isPrimitiveNumber() == false) {
+                // Cannot calculate statistics of a non-primitive number type
+                return@convertToComparableOrNull null
+            }
+            it?.toDouble() as Comparable<Any>?
+        }
 
         else -> null
     }
+}

core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/api/describe.kt

@@ -37,12 +37,12 @@ class DescribeTests {
             nulls shouldBe 1
             top shouldBe 1
             freq shouldBe 1
-            this.mean shouldBe 3.5
+            mean shouldBe 3.5
             std shouldBe 1.8708286933869707
             min shouldBe 1.0
-            p25 shouldBe 2.25
-            median shouldBe 3.5
-            p75 shouldBe 4.75
+            p25 shouldBe 2.0
+            median shouldBe 3.0
+            p75 shouldBe 4.0
             max shouldBe 6.0
         }
     }