Method: Polars::Expr#flatten

Defined in:
lib/polars/expr.rb

#flatten ⇒ Expr

Deprecated.

Expr#flatten is deprecated and will be removed in a future version. Use Expr.list.explode(keep_nulls: false, empty_as_null: false) instead, which provides the behavior you likely expect.

Explode a list or utf8 Series. This means that every item is expanded to a new row.

Alias for #explode.

Examples:

df = Polars::DataFrame.new(
  {
    "group" => ["a", "b", "b"],
    "values" => [[1, 2], [2, 3], [4]]
  }
)
df.group_by("group").agg(Polars.col("values").flatten)
# =>
# shape: (2, 2)
# ┌───────┬───────────┐
# │ group ┆ values    │
# │ ---   ┆ ---       │
# │ str   ┆ list[i64] │
# ╞═══════╪═══════════╡
# │ a     ┆ [1, 2]    │
# │ b     ┆ [2, 3, 4] │
# └───────┴───────────┘

Returns:



3524
3525
3526
 
# File 'lib/polars/expr.rb', line 3524

def flatten
  explode(empty_as_null: true, keep_nulls: true)
end