Fiftyone Code Style

FiftyOne Import Aliases

Docstrings (Google-Style)

Function Docstring

def get_operator(operator_uri, enabled=True):
    """Gets the operator with the given URI.

    Args:
        operator_uri: the operator URI
        enabled (True): whether to include only enabled operators (True) or
            only disabled operators (False) or all operators ("all")

    Returns:
        an :class:`fiftyone.operators.Operator`

    Raises:
        ValueError: if the operator is not found
    """

Class Docstring

class ImageMetadata(Metadata):
    """Class for storing metadata about image samples.

    Args:
        size_bytes (None): the size of the image on disk, in bytes
        mime_type (None): the MIME type of the image
        width (None): the width of the image, in pixels
        height (None): the height of the image, in pixels
    """

Key patterns:

• Args with defaults: param (default): description
• Multi-line descriptions: indent continuation
• Cross-references: :class:fiftyone.module.Class``

Private Functions

# Public API delegates to private helper
def build_for(cls, path_or_url, mime_type=None):
    """Builds a Metadata object for the given file."""
    if path_or_url.startswith("http"):
        return cls._build_for_url(path_or_url, mime_type=mime_type)
    return cls._build_for_local(path_or_url, mime_type=mime_type)

# Private: underscore prefix, focused purpose
def _build_for_local(cls, filepath, mime_type=None):
    """Internal helper for local files."""
    size_bytes = os.path.getsize(filepath)
    if mime_type is None:
        mime_type = etau.guess_mime_type(filepath)
    return cls(size_bytes=size_bytes, mime_type=mime_type)

Lazy Imports

Use fou.lazy_import() for optional/heavy dependencies:

# Basic lazy import
o3d = fou.lazy_import("open3d", callback=lambda: fou.ensure_package("open3d"))

# With ensure_import for pycocotools
mask_utils = fou.lazy_import(
    "pycocotools.mask", callback=lambda: fou.ensure_import("pycocotools")
)

# Internal module lazy import
fop = fou.lazy_import("fiftyone.core.plots.plotly")

When to use:

• Heavy packages (open3d, tensorflow, torch)
• Optional dependencies (pycocotools)
• Circular import prevention

Guard Patterns

Use hasattr() for conditional behavior:

# Check for optional attribute
if hasattr(label, "confidence"):
    if label.confidence is None or label.confidence < threshold:
        label = label.__class__()

# Check for config attribute
if hasattr(eval_info.config, "iscrowd"):
    crowd_attr = eval_info.config.iscrowd