Merge pull request #1081 from Kotlin/to_dataframe_imrovements

To dataframe improvements

Author: AndreiKingsley

core/api/core.api

@@ -5399,6 +5399,8 @@ public final class org/jetbrains/kotlinx/dataframe/impl/api/SchemaKt {
 public final class org/jetbrains/kotlinx/dataframe/impl/api/ToDataFrameKt {
 	public static final fun convertToDataFrame (Ljava/lang/Iterable;Lkotlin/reflect/KClass;Ljava/util/List;Ljava/util/Set;Ljava/util/Set;Ljava/util/Set;I)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
 	public static final fun createDataFrameImpl (Ljava/lang/Iterable;Lkotlin/reflect/KClass;Lkotlin/jvm/functions/Function1;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static final fun getHasProperties (Lkotlin/reflect/KClass;)Z
+	public static final fun isValueType (Lkotlin/reflect/KClass;)Z
 }
 
 public final class org/jetbrains/kotlinx/dataframe/impl/api/ToSequenceKt {

core/generated-sources/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/toDataFrame.kt

@@ -12,6 +12,8 @@ import org.jetbrains.kotlinx.dataframe.annotations.Refine
 import org.jetbrains.kotlinx.dataframe.columns.ColumnPath
 import org.jetbrains.kotlinx.dataframe.impl.ColumnNameGenerator
 import org.jetbrains.kotlinx.dataframe.impl.api.createDataFrameImpl
+import org.jetbrains.kotlinx.dataframe.impl.api.hasProperties
+import org.jetbrains.kotlinx.dataframe.impl.api.isValueType
 import org.jetbrains.kotlinx.dataframe.impl.asList
 import org.jetbrains.kotlinx.dataframe.impl.columnName
 import org.jetbrains.kotlinx.dataframe.impl.columns.createColumnGuessingType
@@ -26,7 +28,15 @@ import kotlin.reflect.KProperty
 @Interpretable("toDataFrameDefault")
 public inline fun <reified T> Iterable<T>.toDataFrame(): DataFrame<T> =
     toDataFrame {
-        properties()
+        // check if type is value: primitives, primitive arrays, datetime types etc.,
+        // or has no properties
+        if (T::class.isValueType || !T::class.hasProperties) {
+            // create a single `value` column
+            ValueProperty<T>::value from { it }
+        } else {
+            // otherwise creates columns based on properties
+            properties()
+        }
     }
 
 @Refine
@@ -217,99 +227,6 @@ public inline fun <reified T> Iterable<T>.toDataFrame(columnName: String): DataF
 
 // region toDataFrame overloads for built-in types
 
-/*
-Without overloads Iterable<String>.toDataFrame produces unexpected result
-
-
-```
-val string = listOf("aaa", "aa", null)
-string.toDataFrame()
-```
-=>
-  length
-0    3
-1    2
-2 null
- */
-
-@JvmName("toDataFrameByte")
-public inline fun <reified B : Byte?> Iterable<B>.toDataFrame(): DataFrame<ValueProperty<B>> =
-    toDataFrame {
-        ValueProperty<B>::value from { it }
-    }.cast()
-
-@JvmName("toDataFrameShort")
-public inline fun <reified S : Short?> Iterable<S>.toDataFrame(): DataFrame<ValueProperty<S>> =
-    toDataFrame {
-        ValueProperty<S>::value from { it }
-    }.cast()
-
-@JvmName("toDataFrameInt")
-public inline fun <reified I : Int?> Iterable<I>.toDataFrame(): DataFrame<ValueProperty<I>> =
-    toDataFrame {
-        ValueProperty<I>::value from { it }
-    }.cast()
-
-@JvmName("toDataFrameLong")
-public inline fun <reified L : Long?> Iterable<L>.toDataFrame(): DataFrame<ValueProperty<L>> =
-    toDataFrame {
-        ValueProperty<L>::value from { it }
-    }.cast()
-
-@JvmName("toDataFrameString")
-public inline fun <reified S : String?> Iterable<S>.toDataFrame(): DataFrame<ValueProperty<S>> =
-    toDataFrame {
-        ValueProperty<S>::value from { it }
-    }.cast()
-
-@JvmName("toDataFrameChar")
-public inline fun <reified C : Char?> Iterable<C>.toDataFrame(): DataFrame<ValueProperty<C>> =
-    toDataFrame {
-        ValueProperty<C>::value from { it }
-    }.cast()
-
-@JvmName("toDataFrameBoolean")
-public inline fun <reified B : Boolean?> Iterable<B>.toDataFrame(): DataFrame<ValueProperty<B>> =
-    toDataFrame {
-        ValueProperty<B>::value from { it }
-    }.cast()
-
-@JvmName("toDataFrameFloat")
-public inline fun <reified F : Float?> Iterable<F>.toDataFrame(): DataFrame<ValueProperty<F>> =
-    toDataFrame {
-        ValueProperty<F>::value from { it }
-    }.cast()
-
-@JvmName("toDataFrameDouble")
-public inline fun <reified D : Double?> Iterable<D>.toDataFrame(): DataFrame<ValueProperty<D>> =
-    toDataFrame {
-        ValueProperty<D>::value from { it }
-    }.cast()
-
-@JvmName("toDataFrameUByte")
-public inline fun <reified U : UByte?> Iterable<U>.toDataFrame(): DataFrame<ValueProperty<U>> =
-    toDataFrame {
-        ValueProperty<U>::value from { it }
-    }.cast()
-
-@JvmName("toDataFrameUShort")
-public inline fun <reified U : UShort?> Iterable<U>.toDataFrame(): DataFrame<ValueProperty<U>> =
-    toDataFrame {
-        ValueProperty<U>::value from { it }
-    }.cast()
-
-@JvmName("toDataFrameUInt")
-public inline fun <reified U : UInt?> Iterable<U>.toDataFrame(): DataFrame<ValueProperty<U>> =
-    toDataFrame {
-        ValueProperty<U>::value from { it }
-    }.cast()
-
-@JvmName("toDataFrameULong")
-public inline fun <reified U : ULong?> Iterable<U>.toDataFrame(): DataFrame<ValueProperty<U>> =
-    toDataFrame {
-        ValueProperty<U>::value from { it }
-    }.cast()
-
 @DataSchema
 public interface ValueProperty<T> {
     public val value: T

core/generated-sources/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/api/toDataFrame.kt

@@ -23,7 +23,8 @@ import org.jetbrains.kotlinx.dataframe.impl.projectUpTo
 import org.jetbrains.kotlinx.dataframe.impl.schema.sortWithConstructor
 import java.lang.reflect.InvocationTargetException
 import java.lang.reflect.Method
-import java.time.temporal.Temporal
+import java.time.temporal.TemporalAccessor
+import java.time.temporal.TemporalAmount
 import kotlin.reflect.KCallable
 import kotlin.reflect.KClass
 import kotlin.reflect.KProperty
@@ -37,23 +38,51 @@ import kotlin.reflect.jvm.isAccessible
 import kotlin.reflect.jvm.javaField
 import kotlin.reflect.typeOf
 
+// non-standard value types (not supertypes, but exact types)
 private val valueTypes = setOf(
+    Any::class,
+    Unit::class,
+    Char::class,
+    UByte::class,
+    UShort::class,
+    UInt::class,
+    ULong::class,
     String::class,
     Boolean::class,
     kotlin.time.Duration::class,
     kotlinx.datetime.LocalDate::class,
     kotlinx.datetime.LocalDateTime::class,
     kotlinx.datetime.Instant::class,
+    kotlinx.datetime.TimeZone::class,
+    kotlinx.datetime.DateTimePeriod::class,
+    kotlinx.datetime.DateTimeUnit::class,
 )
 
+/**
+ * Checks if `KClass` is a value type (number, datetime, string, etc.)
+ * Should be aligned with `ConeKotlinType.isValueType()` in
+ * plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/toDataFrame.kt
+ */
+@PublishedApi
 internal val KClass<*>.isValueType: Boolean
     get() =
         this in valueTypes ||
             this.isSubclassOf(Number::class) ||
             this.isSubclassOf(Enum::class) ||
-            this.isSubclassOf(Temporal::class) ||
+            // all java datetime types
+            this.isSubclassOf(TemporalAccessor::class) ||
+            this.isSubclassOf(TemporalAmount::class) ||
             this.isArray
 
+/**
+ * Checks if `KClass` has public properties / getter functions (for pojo-like classes).
+ */
+@PublishedApi
+internal val KClass<*>.hasProperties: Boolean
+    get() = this.memberProperties.any { it.visibility == KVisibility.PUBLIC } ||
+        // check pojo-like classes
+        this.memberFunctions.any { it.visibility == KVisibility.PUBLIC && it.isGetterLike() }
+
 internal class CreateDataFrameDslImpl<T>(
     override val source: Iterable<T>,
     private val clazz: KClass<*>,