Method: Polars::Expr#cast

Defined in:
lib/polars/expr.rb

#cast(dtype, strict: true) ⇒ Expr

Cast between data types.

Examples:

df = Polars::DataFrame.new(
  {
    "a" => [1, 2, 3],
    "b" => ["4", "5", "6"]
  }
)
df.with_columns(
  [
    Polars.col("a").cast(:f64),
    Polars.col("b").cast(:i32)
  ]
)
# =>
# shape: (3, 2)
# ┌─────┬─────┐
# │ a   ┆ b   │
# │ --- ┆ --- │
# │ f64 ┆ i32 │
# ╞═════╪═════╡
# │ 1.0 ┆ 4   │
# │ 2.0 ┆ 5   │
# │ 3.0 ┆ 6   │
# └─────┴─────┘

Parameters:

  • dtype (Symbol) —

    DataType to cast to.

  • strict (Boolean) (defaults to: true) —

    Throw an error if a cast could not be done. For instance, due to an overflow.

Returns:


1274
1275
1276
1277
 
# File 'lib/polars/expr.rb', line 1274

def cast(dtype, strict: true)
  dtype = Utils.rb_type_to_dtype(dtype)
  _from_rbexpr(_rbexpr.cast(dtype, strict))
end