Nushell

dfr when for expression

Creates and modifies a when expression.

Signature

> dfr when (when expression) (then expression)

Parameters

  • when expression: when expression used for matching
  • then expression: expression that will be applied when predicate is true

Examples

Create a when conditions

> dfr when ((dfr col a) > 2) 4

Create a when conditions

> dfr when ((dfr col a) > 2) 4 | dfr when ((dfr col a) < 0) 6

Create a new column for the dataframe

> [[a b]; [6 2] [1 4] [4 1]]
   | dfr into-lazy
   | dfr with-column (
    dfr when ((dfr col a) > 2) 4 | dfr otherwise 5 | dfr as c
     )
   | dfr with-column (
    dfr when ((dfr col a) > 5) 10 | dfr when ((dfr col a) < 2) 6 | dfr otherwise 0 | dfr as d
     )
   | dfr collect
╭───┬───┬───┬───┬────╮
│ # │ a │ b │ c │ d  │
├───┼───┼───┼───┼────┤
│ 0 │ 6 │ 2 │ 4 │ 10 │
│ 1 │ 1 │ 4 │ 5 │  6 │
│ 2 │ 4 │ 1 │ 4 │  0 │
╰───┴───┴───┴───┴────╯