fiftyone.core.stages.Mongo

A view stage defined by a raw MongoDB aggregation pipeline.

See MongoDB aggregation pipelines for more details.

Examples:

import fiftyone as fo

dataset = fo.Dataset()
dataset.add_samples(
    [
        fo.Sample(
            filepath="/path/to/image1.png",
            predictions=fo.Detections(
                detections=[
                    fo.Detection(
                        label="cat",
                        bounding_box=[0.1, 0.1, 0.5, 0.5],
                        confidence=0.9,
                    ),
                    fo.Detection(
                        label="dog",
                        bounding_box=[0.2, 0.2, 0.3, 0.3],
                        confidence=0.8,
                    ),
                ]
            ),
        ),
        fo.Sample(
            filepath="/path/to/image2.png",
            predictions=fo.Detections(
                detections=[
                    fo.Detection(
                        label="cat",
                        bounding_box=[0.5, 0.5, 0.4, 0.4],
                        confidence=0.95,
                    ),
                    fo.Detection(label="rabbit"),
                ]
            ),
        ),
        fo.Sample(
            filepath="/path/to/image3.png",
            predictions=fo.Detections(
                detections=[
                    fo.Detection(
                        label="squirrel",
                        bounding_box=[0.25, 0.25, 0.5, 0.5],
                        confidence=0.5,
                    ),
                ]
            ),
        ),
        fo.Sample(
            filepath="/path/to/image4.png",
            predictions=None,
        ),
    ]
)

#
# Extract a view containing the second and third samples in the dataset
#

stage = fo.Mongo([{"$skip": 1}, {"$limit": 2}])
view = dataset.add_stage(stage)

#
# Sort by the number of objects in the `precictions` field
#

stage = fo.Mongo([
    {
        "$addFields": {
            "_sort_field": {
                "$size": {"$ifNull": ["$predictions.detections", []]}
            }
        }
    },
    {"$sort": {"_sort_field": -1}},
    {"$project": {"_sort_field": False}},
])
view = dataset.add_stage(stage)