MarcinMoskala

def add_day_month_year(df):
    dates = df["Date"].map(lambda x: x[:10])
    df["day_of_month"] = dates.map(lambda x: x.split("/")[1])
    df["month"] = dates.map(lambda x: x.split("/")[0])
    df["year"] = dates.map(lambda x: x.split("/")[2])
    df["date"] = dates
    return df


from pandas import read_csv

MarcinMoskala

def add_day_month_year(df):
    dates = df["Date"].map(lambda x: x[:10])
    df["day_of_month"] = dates.map(lambda x: x.split("/")[1])
    df["month"] = dates.map(lambda x: x.split("/")[0])
    df["year"] = dates.map(lambda x: x.split("/")[2])
    df["date"] = dates
    return df


from pandas import read_csv

MarcinMoskala

data class Student(
    val id: Int,
    val name: String,
    val surname: String
)
    
class StudentsFactory {
    var nextId = 0
    fun next(name: String, surname: String) =
        Student(nextId++, name, surname)

MarcinMoskala

// Constructor:
val f: ()->Tree = ::Tree
// Fake constructor:
val f: ()->Tree = ::Tree
// Invoke in companion object:
val f: ()->Tree = Tree.Companion::invoke

MarcinMoskala

// Constructor:
val f: ()->Tree = ::Tree
// Fake constructor:
val f: ()->Tree = ::Tree
// Invoke in companion object:
val f: ()->Tree = Tree.Companion::invoke

MarcinMoskala

Tree.invoke(10) { "$it" }

MarcinMoskala

class Tree<T> {
    
    companion object {
        operator fun <T> invoke(size: Int, generator: (Int)->T): Tree<T>{
           //…
        }
    }
}
// Usage
Tree(10) { "$it" }

MarcinMoskala

public inline fun <T> List(
    size: Int,
    init: (index: Int) -> T
): List<T> = MutableList(size, init)
    
public inline fun <T> MutableList(
    size: Int,
    init: (index: Int) -> T
): MutableList<T> {
    val list = ArrayList<T>(size)

MarcinMoskala

List(4) { "User$it" } // [User0, User1, User2, User3]

MarcinMoskala

val reference: ()->A = ::A