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Merged
merged 2 commits into from
Sep 18, 2023
Merged

Public empty(DataFrameSchema) API #452

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1461d27
add docstring to GroupByImpl class
koperagen Sep 8, 2023
a4490b2
add public API to create dataframes with empty columns by a schema
koperagen Sep 8, 2023
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13 changes: 13 additions & 0 deletions core/generated-sources/src/main/kotlin/org/jetbrains/kotlinx/dataframe/DataFrame.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,9 @@ import org.jetbrains.kotlinx.dataframe.impl.DataFrameSize
import org.jetbrains.kotlinx.dataframe.impl.getColumnsImpl
import org.jetbrains.kotlinx.dataframe.impl.headPlusArray
import org.jetbrains.kotlinx.dataframe.impl.headPlusIterable
import org.jetbrains.kotlinx.dataframe.impl.schema.createEmptyDataFrame
import org.jetbrains.kotlinx.dataframe.impl.schema.createEmptyDataFrameOf
import org.jetbrains.kotlinx.dataframe.schema.DataFrameSchema
import kotlin.reflect.KType

/**
Expand All @@ -32,7 +34,18 @@ public interface DataFrame<out T> : Aggregatable<T>, ColumnsContainer<T> {
public val Empty: AnyFrame = DataFrameImpl<Unit>(emptyList(), 0)
public fun empty(nrow: Int = 0): AnyFrame = if (nrow == 0) Empty else DataFrameImpl<Unit>(emptyList(), nrow)

/**
* Creates a DataFrame with empty columns (rows = 0).
* Can be used as a "null object" in aggregation operations, operations that work on columns (select, reorder, ...)
*
*/
public inline fun <reified T> emptyOf(): DataFrame<T> = createEmptyDataFrameOf(T::class).cast()

/**
* Creates a DataFrame with empty columns (rows = 0).
* Can be used as a "null object" in aggregation operations, operations that work on columns (select, reorder, ...)
*/
public fun empty(schema: DataFrameSchema): AnyFrame = schema.createEmptyDataFrame()
}

// region columns
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3 changes: 3 additions & 0 deletions core/generated-sources/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/GroupByImpl.kt
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Expand Up @@ -20,6 +20,9 @@ import org.jetbrains.kotlinx.dataframe.ncol
import org.jetbrains.kotlinx.dataframe.nrow
import org.jetbrains.kotlinx.dataframe.values

/**
* @property df DataFrame containing [groups] column and key columns. Represents GroupBy.
*/
internal class GroupByImpl<T, G>(
val df: DataFrame<T>,
override val groups: FrameColumn<G>,
Expand Down
24 changes: 24 additions & 0 deletions ...sources/src/test/kotlin/org/jetbrains/kotlinx/dataframe/testSets/person/DataFrameTests.kt
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Expand Up @@ -2383,4 +2383,28 @@ class DataFrameTests : BaseTest() {
val newName by column<String>()
typed.select { name into newName and age }.columnNames() shouldBe listOf("newName", "age")
}

@Test
fun `api for creating GroupBy with empty groups which can be aggregated using statistics`() {
val df1 = dataFrameOf("a", "b")(1, "c")
val df2 = DataFrame.empty()
val groupBy = dataFrameOf(columnOf("group1", "group2") named "group", columnOf(df1, df2)).asGroupBy()

val exception = shouldThrow<IllegalStateException> {
groupBy.aggregate {
sum("a")
}
}

exception.message shouldBe "Column [a] not found"

val groupBy1 = groupBy
.updateGroups { if (it.isEmpty()) DataFrame.empty(groupBy.groups.schema.value) else it }

val res = groupBy1.aggregate {
sum("a")
}

res["aggregated"].values() shouldBe listOf(1, 0)
}
}
13 changes: 13 additions & 0 deletions core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/DataFrame.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,9 @@ import org.jetbrains.kotlinx.dataframe.impl.DataFrameSize
import org.jetbrains.kotlinx.dataframe.impl.getColumnsImpl
import org.jetbrains.kotlinx.dataframe.impl.headPlusArray
import org.jetbrains.kotlinx.dataframe.impl.headPlusIterable
import org.jetbrains.kotlinx.dataframe.impl.schema.createEmptyDataFrame
import org.jetbrains.kotlinx.dataframe.impl.schema.createEmptyDataFrameOf
import org.jetbrains.kotlinx.dataframe.schema.DataFrameSchema
import kotlin.reflect.KType

/**
Expand All @@ -32,7 +34,18 @@ public interface DataFrame<out T> : Aggregatable<T>, ColumnsContainer<T> {
public val Empty: AnyFrame = DataFrameImpl<Unit>(emptyList(), 0)
public fun empty(nrow: Int = 0): AnyFrame = if (nrow == 0) Empty else DataFrameImpl<Unit>(emptyList(), nrow)

/**
* Creates a DataFrame with empty columns (rows = 0).
* Can be used as a "null object" in aggregation operations, operations that work on columns (select, reorder, ...)
*
*/
public inline fun <reified T> emptyOf(): DataFrame<T> = createEmptyDataFrameOf(T::class).cast()

/**
* Creates a DataFrame with empty columns (rows = 0).
* Can be used as a "null object" in aggregation operations, operations that work on columns (select, reorder, ...)
*/
public fun empty(schema: DataFrameSchema): AnyFrame = schema.createEmptyDataFrame()
}

// region columns
Expand Down
3 changes: 3 additions & 0 deletions core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/GroupByImpl.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,9 @@ import org.jetbrains.kotlinx.dataframe.ncol
import org.jetbrains.kotlinx.dataframe.nrow
import org.jetbrains.kotlinx.dataframe.values

/**
* @property df DataFrame containing [groups] column and key columns. Represents GroupBy.
*/
internal class GroupByImpl<T, G>(
val df: DataFrame<T>,
override val groups: FrameColumn<G>,
Expand Down
24 changes: 24 additions & 0 deletions core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/testSets/person/DataFrameTests.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -2383,4 +2383,28 @@ class DataFrameTests : BaseTest() {
val newName by column<String>()
typed.select { name into newName and age }.columnNames() shouldBe listOf("newName", "age")
}

@Test
fun `api for creating GroupBy with empty groups which can be aggregated using statistics`() {
val df1 = dataFrameOf("a", "b")(1, "c")
val df2 = DataFrame.empty()
val groupBy = dataFrameOf(columnOf("group1", "group2") named "group", columnOf(df1, df2)).asGroupBy()

val exception = shouldThrow<IllegalStateException> {
groupBy.aggregate {
sum("a")
}
}

exception.message shouldBe "Column [a] not found"

val groupBy1 = groupBy
.updateGroups { if (it.isEmpty()) DataFrame.empty(groupBy.groups.schema.value) else it }

val res = groupBy1.aggregate {
sum("a")
}

res["aggregated"].values() shouldBe listOf(1, 0)
}
}