Method: Polars::Expr#slice

Defined in:

lib/polars/expr.rb

#slice(offset, length = nil) ⇒ Expr

Get a slice of this expression.

Examples:

df = Polars::DataFrame.new(
  {
    "a" => [8, 9, 10, 11],
    "b" => [nil, 4, 4, 4]
  }
)
df.select(Polars.all.slice(1, 2))
# =>
# shape: (2, 2)
# ┌─────┬─────┐
# │ a   ┆ b   │
# │ --- ┆ --- │
# │ i64 ┆ i64 │
# ╞═════╪═════╡
# │ 9   ┆ 4   │
# │ 10  ┆ 4   │
# └─────┴─────┘

Parameters:

• offset (Integer) —

  Start index. Negative indexing is supported.

• length (Integer) (defaults to: nil) —

  Length of the slice. If set to nil, all rows starting at the offset will be selected.

Returns:

• (Expr)

# File 'lib/polars/expr.rb', line 814

def slice(offset, length = nil)
  if !offset.is_a?(Expr)
    offset = Polars.lit(offset)
  end
  if !length.is_a?(Expr)
    length = Polars.lit(length)
  end
  _from_rbexpr(_rbexpr.slice(offset._rbexpr, length._rbexpr))
end