add DataColumn.none

Author: CarloMariaProietti

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

@@ -1,13 +1,24 @@
 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.size
+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] or [values] is empty. */
+public fun <T> DataColumn<T>.none(predicate: Predicate<T>): Boolean = values.none(predicate)
+
+// endregion
+
 // region DataFrame
 
 /**

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

@@ -18,6 +18,13 @@ 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