Method: Polars::Expr#get

Defined in:

lib/polars/expr.rb

#get(index) ⇒ Expr

Return a single value by index.

Examples:

df = Polars::DataFrame.new(
  {
    "group" => [
      "one",
      "one",
      "one",
      "two",
      "two",
      "two"
    ],
    "value" => [1, 98, 2, 3, 99, 4]
  }
)
df.group_by("group", maintain_order: true).agg(Polars.col("value").get(1))
# =>
# shape: (2, 2)
# ┌───────┬───────┐
# │ group ┆ value │
# │ ---   ┆ ---   │
# │ str   ┆ i64   │
# ╞═══════╪═══════╡
# │ one   ┆ 98    │
# │ two   ┆ 99    │
# └───────┴───────┘

Parameters:

• index (Object) —

  An expression that leads to a UInt32 index.

Returns:

• (Expr)

# File 'lib/polars/expr.rb', line 1672

def get(index)
  index_lit = Utils.parse_into_expression(index)
  _from_rbexpr(_rbexpr.get(index_lit))
end