daft.functions.map_get#

def map_get(expr: Expression, key: Expression) -> Expression:
    """Retrieves the value for a key in a map column.

    Args:
        expr: the map expression to get from
        key: the key to retrieve

    Returns:
        Expression: the value expression

    Examples:
        >>> import pyarrow as pa
        >>> import daft
        >>> pa_array = pa.array([[("a", 1)], [], [("b", 2)]], type=pa.map_(pa.string(), pa.int64()))
        >>> df = daft.from_arrow(pa.table({"map_col": pa_array}))
        >>> df = df.with_column("a", df["map_col"].map_get("a"))
        >>> df.show()
        ╭────────────────────┬───────╮
        │ map_col            ┆ a     │
        │ ---                ┆ ---   │
        │ Map[String: Int64] ┆ Int64 │
        ╞════════════════════╪═══════╡
        │ {"a": 1}           ┆ 1     │
        ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┤
        │ {}                 ┆ None  │
        ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┤
        │ {"b": 2}           ┆ None  │
        ╰────────────────────┴───────╯
        <BLANKLINE>
        (Showing first 3 of 3 rows)

    """
    key_expr = Expression._to_expression(key)
    return Expression._from_pyexpr(expr._expr.map_get(key_expr._expr))