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daft.functions.guess_mime_type#

guess_mime_type #

guess_mime_type(bytes_expr: Expression) -> Expression

Guess the MIME type of binary data by inspecting magic bytes.

Detects common file formats including: PNG, JPEG, GIF, WEBP, PDF, ZIP, MP3, WAV, OGG, MP4, MPEG, and HTML. Returns None if the format cannot be determined.

Parameters:

Name Type Description Default
bytes_expr Expression

Binary expression containing raw bytes.

 required

Returns:

Name Type Description
Expression Expression

String expression containing MIME type (e.g., "image/png") or None.
Example

import daft from daft.functions import guess_mime_type df = daft.from_pydict({"data": [b"\x89PNG\r\n\x1a\n", b"not a known format"]}) df = df.with_column("mime", guess_mime_type(df["data"])) df.select("mime").show() ╭───────────╮ │ mime │ │ --- │ │ String │ ╞═══════════╡ │ image/png │ ├╌╌╌╌╌╌╌╌╌╌╌┤ │ None │ ╰───────────╯ (Showing first 2 of 2 rows)

Source code in daft/functions/file_.py 
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def guess_mime_type(bytes_expr: Expression) -> Expression:
    r"""Guess the MIME type of binary data by inspecting magic bytes.

    Detects common file formats including: PNG, JPEG, GIF, WEBP, PDF, ZIP,
    MP3, WAV, OGG, MP4, MPEG, and HTML. Returns None if the format cannot
    be determined.

    Args:
        bytes_expr: Binary expression containing raw bytes.

    Returns:
        Expression: String expression containing MIME type (e.g., "image/png") or None.

    Example:
        >>> import daft
        >>> from daft.functions import guess_mime_type
        >>> df = daft.from_pydict({"data": [b"\x89PNG\r\n\x1a\n", b"not a known format"]})
        >>> df = df.with_column("mime", guess_mime_type(df["data"]))
        >>> df.select("mime").show()
        ╭───────────╮
        │ mime      │
        │ ---       │
        │ String    │
        ╞═══════════╡
        │ image/png │
        ├╌╌╌╌╌╌╌╌╌╌╌┤
        │ None      │
        ╰───────────╯
        <BLANKLINE>
        (Showing first 2 of 2 rows)

    """
    return bytes_expr._eval_expressions("guess_mime_type")