daft.functions.slice#

def slice(expr: Expression, start: int | Expression, end: int | Expression | None = None) -> Expression:
    r"""Get a subset of each list or binary value.

    Args:
        expr: List or binary expression to slice.
        start: Index or column of indices. The slice will include elements starting from this index. If `start` is negative, it represents an offset from the end
        end: Index or column of indices. The slice will not include elements from this index onwards. If `end` is negative, it represents an offset from the end. If not provided, the slice will include elements up to the end of the list. If start > end, an empty slice is produced.

    Returns:
        Expression: an expression with the same type as the input.

    Note:
        `expr[start:stop]` is also equivalent to `expr.slice(start, stop)`

    Examples:
        Slicing a list expression:
        >>> import daft
        >>> df = daft.from_pydict({"x": [[1, 2, 3], [4, 5, 6, 7], [8]]})
        >>> df = df.select(df["x"].slice(1, -1))
        >>> df.show()
        ╭─────────────╮
        │ x           │
        │ ---         │
        │ List[Int64] │
        ╞═════════════╡
        │ [2]         │
        ├╌╌╌╌╌╌╌╌╌╌╌╌╌┤
        │ [5, 6]      │
        ├╌╌╌╌╌╌╌╌╌╌╌╌╌┤
        │ []          │
        ╰─────────────╯
        <BLANKLINE>
        (Showing first 3 of 3 rows)

        Slicing a binary expression:
        >>> df = daft.from_pydict({"x": [b"Hello World", b"\xff\xfe\x00", b"empty"]})
        >>> df = df.select(df["x"].slice(1, -2))
        >>> df.show()
        ╭─────────────╮
        │ x           │
        │ ---         │
        │ Binary      │
        ╞═════════════╡
        │ b"ello Wor" │
        ├╌╌╌╌╌╌╌╌╌╌╌╌╌┤
        │ b""         │
        ├╌╌╌╌╌╌╌╌╌╌╌╌╌┤
        │ b"mp"       │
        ╰─────────────╯
        <BLANKLINE>
        (Showing first 3 of 3 rows)
    """
    return Expression._call_builtin_scalar_fn("slice", expr, start, end=end)