import org.jetbrains.kotlinx.dataframe.* import org.jetbrains.kotlinx.dataframe.annotations.* import org.jetbrains.kotlinx.dataframe.api.* import org.jetbrains.kotlinx.dataframe.io.* fun box(): String { // multiple columns val personsDf = dataFrameOf("name", "age", "city", "weight", "height", "yearsToRetirement")( "Alice", 15, "London", 99.5, "1.85", 50, "Bob", 20, "Paris", 140.0, "1.35", 45, "Charlie", 100, "Dubai", 75.0, "1.95", 0, "Rose", 1, "Moscow", 45.33, "0.79", 64, "Dylan", 35, "London", 23.4, "1.83", 30, "Eve", 40, "Paris", 56.72, "1.85", 25, "Frank", 55, "Dubai", 78.9, "1.35", 10, "Grace", 29, "Moscow", 67.8, "1.65", 36, "Hank", 60, "Paris", 80.22, "1.75", 5, "Isla", 22, "London", 75.1, "1.85", 43, ) // scenario #0: all numerical columns val res0 = personsDf.groupBy { city }.max() val max01: Int? = res0.age[0] val max02: Double? = res0.weight[0] res0.compareSchemas() // scenario #1: particular column val res1 = personsDf.groupBy { city }.maxFor { age } val max11: Int? = res1.age[0] res1.compareSchemas() // scenario #1.1: particular column via max val res11 = personsDf.groupBy { city }.max { age } val max111: Int? = res11.age[0] res11.compareSchemas() // scenario #2: particular column with new name - schema changes // TODO: not supported scenario // val res2 = personsDf.groupBy { city }.max("age", name = "newAge") // val max21: Int? = res2.newAge[0] // scenario #2.1: particular column with new name - schema changes but via columnSelector val res21 = personsDf.groupBy { city }.max("newAge") { age } val max211: Int? = res21.newAge[0] res21.compareSchemas() // scenario #2.2: two columns with new name - schema changes but via columnSelector // TODO: handle multiple columns https://github.com/Kotlin/dataframe/issues/1090 val res22 = personsDf.groupBy { city }.max("newAge") { age and yearsToRetirement } val max221: Int? = res22.newAge[0] res22.compareSchemas() // scenario #3: create new column via expression val res3 = personsDf.groupBy { city }.maxOf("newAge") { age / 10 } val max3: Int? = res3.newAge[0] res3.compareSchemas() return "OK" }