Merge pull request #1462 from CarloMariaProietti/add_none_to_df

adding `.none {}` to `DataFrame`

Author: Jolanrensen

core/api/core.api

@@ -3471,6 +3471,11 @@ public abstract interface class org/jetbrains/kotlinx/dataframe/api/NoneColumnsS
 public abstract interface class org/jetbrains/kotlinx/dataframe/api/NoneColumnsSelectionDsl$Grammar$PlainDslName {
 }
 
+public final class org/jetbrains/kotlinx/dataframe/api/NoneKt {
+	public static final fun none (Lorg/jetbrains/kotlinx/dataframe/DataColumn;Lkotlin/jvm/functions/Function1;)Z
+	public static final fun none (Lorg/jetbrains/kotlinx/dataframe/DataFrame;Lkotlin/jvm/functions/Function2;)Z
+}
+
 public final class org/jetbrains/kotlinx/dataframe/api/NullabilityException : java/lang/Exception {
 	public fun <init> ()V
 }

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/none.kt

@@ -1,11 +1,45 @@
 package org.jetbrains.kotlinx.dataframe.api
 
+import org.jetbrains.kotlinx.dataframe.DataColumn
 import org.jetbrains.kotlinx.dataframe.DataFrame
+import org.jetbrains.kotlinx.dataframe.DataRow
+import org.jetbrains.kotlinx.dataframe.Predicate
+import org.jetbrains.kotlinx.dataframe.RowFilter
 import org.jetbrains.kotlinx.dataframe.columns.ColumnSet
 import org.jetbrains.kotlinx.dataframe.columns.ColumnsResolver
+import org.jetbrains.kotlinx.dataframe.columns.values
 import org.jetbrains.kotlinx.dataframe.documentation.DslGrammarTemplateColumnsSelectionDsl.DslGrammarTemplate
 import org.jetbrains.kotlinx.dataframe.impl.columns.ColumnListImpl
 
+// region DataColumn
+
+/** Returns `true` if none of the [values] match the given [predicate] */
+public fun <T> DataColumn<T>.none(predicate: Predicate<T>): Boolean = values.none(predicate)
+
+// endregion
+
+// region DataFrame
+
+/**
+ * Returns `true` if none of the rows in this [DataFrame] satisfies the given [predicate].
+ *
+ * {@include [org.jetbrains.kotlinx.dataframe.documentation.RowFilterDescription]}
+ *
+ * ### Example
+ * ```kotlin
+ * // Check if there is not any row where "age" is greater than 18
+ * val hasNoAdults = df.none { age > 18 }
+ * ```
+ *
+ * @param predicate A [RowFilter] lambda that takes a [DataRow] (as both `this` and `it`)
+ * and returns `true` if none of the rows should be considered a match.
+ * @return `true` if none of the rows satisfies the [predicate], `false` otherwise.
+ * @see [DataFrame.any]
+ */
+public inline fun <T> DataFrame<T>.none(predicate: RowFilter<T>): Boolean = rows().none { predicate(it, it) }
+
+// endregion
+
 // region ColumnsSelectionDsl
 
 /**

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

@@ -18,12 +18,25 @@ class UtilFunctionsTest : TestBase() {
         ageCol.any { it > 90 } shouldBe false
     }
 
+    @Test
+    fun `DataColumn none`() {
+        val ageCol = df["age"] as DataColumn<Int>
+        ageCol.none { it > 40 } shouldBe false
+        ageCol.none { it > 90 } shouldBe true
+    }
+
     @Test
     fun `DataFrame any`() {
         df.any { "age"<Int>() > 40 && "isHappy"<Boolean>() } shouldBe true
         df.any { "city"<String?>() == "Berlin" } shouldBe false
     }
 
+    @Test
+    fun `DataFrame none`() {
+        df.none { "age"<Int>() > 40 && "isHappy"<Boolean>() } shouldBe false
+        df.none { "city"<String?>() == "Berlin" } shouldBe true
+    }
+
     @Test
     fun `DataColumn between`() {
         val ages = listOf(15, 45, 20, 40, 30, 20, 30)