init research

dataframe/plugins/kotlin-dataframe/testData/box/selectThis.kt

@@ -0,0 +1,13 @@
+import org.jetbrains.kotlinx.dataframe.*
+import org.jetbrains.kotlinx.dataframe.annotations.*
+import org.jetbrains.kotlinx.dataframe.api.*
+import org.jetbrains.kotlinx.dataframe.io.*
+
+data class Record(val a: String, val b: Int)
+
+fun box(): String {
+    val df = listOf(Record("112", 42)).toDataFrame(maxDepth = 1)
+    val df1 = df.select { this.a }
+    df1.a
+    return "OK"
+}