试图从 json 文件中删除特定项目

Question

我正在尝试删除“注释”列表中的所有项目，并将值 7 作为“类别 ID”。 每次运行代码时，function 都会返回一个未删除此特定条目的列表。 最终目标是更改大量特定标签的类别 ID，并删除所有其他标签。

这是我现在的代码

annotations_test = 'test_annotations/_annotations.coco_test.json'
annotations_train = 'train/_annotations.coco.json'

def delete(annotations_test):
    with open(annotations_test, "r") as data_file:
        data = json.load(data_file)
        for i in range(1, len(data["annotations"])):
            len_after=len(data["annotations"])
            if i == len_after:
                print(data)
                return data
            if data["annotations"][i]['category_id'] == 7:
                del data["annotations"][i]
                i = i - 1

JSON 文件如下所示。

{
    "categories": [
         {
            "id": 0,
            "name": "Teeth",
            "supercategory": "none"
        },
      
    ],
    "images": [
        {
            "id": 0,
            "license": 1,
            "file_name": "Output13_jpg.rf.7422a2210c5a09d832d2e0c3d8a765ee.jpg",
            "height": 416,
            "width": 416,
            "date_captured": "2022-04-22T13:07:04+00:00"
        },
        {
            "id": 1,
            "license": 1,
            "file_name": "Output9_jpg.rf.f8ae8e69ef667a8883518fafff1470c0.jpg",
            "height": 416,
            "width": 416,
            "date_captured": "2022-04-22T13:07:04+00:00"
        }
    ],
    "annotations": [
        {
            "id": 0,
            "image_id": 0,
            "category_id": 7,
            "bbox": [
                179,
                43,
                20.5,
                23.5
            ],
            "area": 481.75,
            "segmentation": [],
            "iscrowd": 0
        },
        {
            "id": 1,
            "image_id": 0,
            "category_id": 3,
            "bbox": [
                240,
                54,
                20.5,
                23.5
            ],
            "area": 481.75,
            "segmentation": [],
            "iscrowd": 0
        }

Answer 1

在您循环的列表上使用del不是一个好主意。

如果您想要的是 category_id 不为 7 的注释列表，则可以使用列表理解。

with open(annotations_test, "r") as data_file:
    data = json.load(data_file)
    return [annotation for annotation in  data["annotations"] if annotation['category_id'] != 7]

如果您需要仅更新注释的整个 json 数据。

with open(annotations_test, "r") as data_file:
    data = json.load(data_file)
    without_7 = [annotation for annotation in  data["annotations"] if annotation['category_id'] != 7]
    data["annotations"] = without_7
    return data