Add a way to create hierarchical dataframes without variables

[koperagen]

So this is supported

// DataFrame with 2 columns and 3 rows
val df = dataFrameOf(
    "name" to listOf("Alice", "Bob", "Charlie"),
    "age" to listOf(15, 20, 100)
)

But if you want to create columnGroup, you'll have to completely rewrite your code:

val name by columnOf(...) or val name = listOf().toColumn()
val age = ...
val group by columnOf(name, age)
val df = dataFrameof(group)

[zaleslaw]

We add you @AndreiKingsley to be a watcher here, not the implementer

[koperagen]

I have two options in mind

dataFrameOf {
  "name" from listOf("Alice", "Bob", "Charlie")
  "age" from listOf(15, 20, 100)
  "group" { 
     "name" from listOf("Alice", "Bob", "Charlie")
      "age" from listOf(15, 20, 100)
  }
}

Or

val df = dataFrameOf(
    "name" to listOf("Alice", "Bob", "Charlie"),
    "age" to listOf(15, 20, 100),
    "group" to columnGroupOf(
          "name" to listOf("Alice", "Bob", "Charlie"),
          "age" to listOf(15, 20, 100),
    )
)

But biggest disadvantage, columnGroupOf must return List (which contradicts its name). I like second option more because it's simple.

[AndreiKingsley]

@koperagen what's problem with

val df = dataFrameOf(
    "name" to columnOf("Alice", "Bob", "Charlie"),
    "age" to columnOf(15, 20, 100),
    "group" to columnGroupOf(
          "name" to listOf("Alice", "Bob", "Charlie"),
          "age" to listOf(15, 20, 100),
    )
)

[koperagen]

@koperagen what's problem with

val df = dataFrameOf(
    "name" to columnOf("Alice", "Bob", "Charlie"),
    "age" to columnOf(15, 20, 100),
    "group" to columnGroupOf(
          "name" to listOf("Alice", "Bob", "Charlie"),
          "age" to listOf(15, 20, 100),
    )
)

Nice idea

[koperagen]

more consistent api:

val df = dataFrameOf(
    "name" to columnOf("Alice", "Bob", "Charlie"),
    "age" to columnOf(15, 20, 100),
    "group" to columnGroupOf(
          "name" to columnOf("Alice", "Bob", "Charlie"),
          "age" to columnOf(15, 20, 100),
    )
)

[koperagen]

fixed in #1144