Tag¶

class Tag(meta, value=None, sly_id=None, labeler_login=None, updated_at=None, created_at=None)[source]¶

Bases: KeyObject

Tag attached to image or label; meta + value. Immutable.

Parameters:

meta¶: TagMeta object with tag metadata (name, value type).
value : str or int or float, optional¶: Tag value; type must match TagMeta.value_type. Date tag values must be ISO datetime strings.
sly_id : int, optional¶: Server-side tag ID.
labeler_login : str, optional¶: Login of user who created the tag.
updated_at : str, optional¶: Last modification timestamp (ISO format).
created_at : str, optional¶: Creation timestamp (ISO format).

Raises:

ValueError – If meta is None or value is incompatible with TagMeta.value_type.

Usage Example:

import supervisely as sly

meta_dog = sly.TagMeta('dog', sly.TagValueType.NONE)
tag_dog = sly.Tag(meta_dog)

meta_cat = sly.TagMeta('cat', sly.TagValueType.ANY_STRING)
tag_cat = sly.Tag(meta_cat, value="Fluffy")

colors = ["brown", "white", "black"]
meta_coat = sly.TagMeta('coat color', sly.TagValueType.ONEOF_STRING, possible_values=colors)
tag_coat = sly.Tag(meta_coat, value="white")

meta_date = sly.TagMeta('reviewed_at', sly.TagValueType.DATE)
tag_date = sly.Tag(meta_date, value="2026-04-23T15:15:48")

Methods

`clone`	Clone makes a copy of Tag with new fields, if fields are given, otherwise it will use original Tag fields.
`from_json`	Convert a json dict to Tag.
`get_compact_str`	Displays information about Tag's name and value in string format.
`get_header_ptable`	Get header of the table with tags.
`get_row_ptable`	Get row with tag properties.
`key`	Get TagMeta key value.
`to_json`	Convert the Tag to a json dict.

Attributes

`meta`	General information about Tag.
`name`	Name property.
`value`	Tag value.

classmethod from_json(data, tag_meta_collection)[source]¶

Convert a json dict to Tag. Read more about Supervisely format.

Parameters:

data : dict¶: Tag in json format as a dict.
tag_meta_collection¶: TagMetaCollection object.

Returns:

Tag object

Return type:

Tag

Usage Example:

import supervisely as sly

meta_dog = sly.TagMeta('dog', sly.TagValueType.ANY_STRING)
tag_metas = sly.TagMetaCollection([meta_dog])

data = {
    "name": "dog",
    "value": "Husky",
    "labelerLogin": "admin",
    "updatedAt": "2021-01-22T19:37:50.158Z",
    "createdAt": "2021-01-22T18:00:00.000Z"
}

tag_dog = sly.Tag.from_json(data, tag_metas)

classmethod get_header_ptable()[source]¶

Get header of the table with tags.

Returns:

List of table header values.

Return type:

List[str]

Usage Example:

import supervisely as sly

header = sly.Tag.get_header_ptable()

print(header)
# Output: ['Name', 'Value type', 'Value']

clone(meta=None, value=None, sly_id=None, labeler_login=None, updated_at=None, created_at=None)[source]¶

Clone makes a copy of Tag with new fields, if fields are given, otherwise it will use original Tag fields.

Parameters:

meta=None¶: General information about Tag.
sly_id : int, optional¶: Tag ID in Supervisely server.
labeler_login : str, optional¶: Login of user who created Tag.
updated_at : str, optional¶: Date and Time when Tag was modified last. Date Format: Year:Month:Day:Hour:Minute:Seconds. Example: ‘2021-01-22T19:37:50.158Z’.
created_at : str, optional¶: Date and Time when Tag was created. Date Format is the same as in “updated_at” parameter.

Returns:

New instance of Tag object

Return type:

Tag

Usage Example:

import supervisely as sly

#Original Tag
weather_conditions = ["Sunny", "Cloudy", "Snowy", "Foggy", "Rainy"]
meta_weather = sly.TagMeta("weather", sly.TagValueType.ONEOF_STRING, possible_values=weather_conditions)

tag_weather = sly.Tag(meta_weather, value="Sunny")

# Let's create some more tags by cloning our original Tag
# Remember that Tag class object is immutable, and we need to assign new instance of Tag to a new variable
clone_weather_1 = tag_weather.clone(value="Snowy")

clone_weather_2 = tag_weather.clone(value="Cloudy")

clone_weather_3 = tag_weather.clone(value="Rainy")

get_compact_str()[source]¶

Displays information about Tag’s name and value in string format.

Returns:

Name and value of the given Tag

Return type:

str

Usage Example:

import supervisely as sly

meta_dog = sly.TagMeta('dog', sly.TagValueType.ANY_STRING)
tag_dog = sly.Tag(meta_dog, value="Husky")

print(tag_dog.get_compact_str())
# Output: 'dog:Husky'

get_row_ptable()[source]¶

Get row with tag properties.

Returns:

List of tag properties.

Return type:

List[str]

Usage Example:

import supervisely as sly

weather_conditions = ["Sunny", "Cloudy", "Snowy", "Foggy", "Rainy"]
meta_weather = sly.TagMeta("weather", sly.TagValueType.ONEOF_STRING, possible_values=weather_conditions)
tag_weather = sly.Tag(meta_weather, value="Sunny")

row = tag_weather.get_row_ptable()

print(row)
# Output: ['weather', 'oneof_string', 'Sunny']

key()[source]¶

Get TagMeta key value.

Returns:

TagMeta key value

Return type:

str

Usage Example:

import supervisely as sly

weather_conditions = ["Sunny", "Cloudy", "Snowy", "Foggy", "Rainy"]
meta_weather = sly.TagMeta("weather", sly.TagValueType.ONEOF_STRING, possible_values=weather_conditions)
tag_weather = sly.Tag(meta_weather, value="Sunny")
key = tag_weather.key()
print(key)
# Output: weather

to_json()[source]¶

Convert the Tag to a json dict. Read more about Supervisely format.

Returns:

Json format as a dict

Return type:

dict

Usage Example:

import supervisely as sly

# Tag with all fields filled in
meta_dog = sly.TagMeta('dog', sly.TagValueType.ANY_STRING)
tag_dog = sly.Tag(
    meta=meta_dog,
    value="Husky",
    sly_id=38456,
    labeler_login="admin",
    updated_at="2021-01-22T19:37:50.158Z",
    created_at="2021-01-22T18:00:00.000Z"
)

tag_dog_json = tag_dog.to_json()
print(tag_dog_json)
# Notice that sly_id won't print
# Output: {
#  "name": "dog",
#  "value": "Husky",
#  "labelerLogin": "admin",
#  "updatedAt": "2021-01-22T19:37:50.158Z",
#  "createdAt": "2021-01-22T18:00:00.000Z"
# }

property meta : supervisely.annotation.tag_meta.TagMeta¶

General information about Tag. When creating a new Tag, it’s value is automatically cross-checked against TagValueType to make sure that value is valid.

Returns:

TagMeta object

Return type:

TagMeta

Usage Example:

meta_dog = sly.TagMeta('dog', sly.TagValueType.NONE)
tag_dog = sly.Tag(meta_dog)

# Our TagMeta has value type 'NONE', if we try to add value to our Tag, "ValueError" error will be raised
tag_dog = sly.Tag(meta_dog, value="Husky")
# Output: ValueError: Tag dog can not have value Husky

property name : str¶

Name property.

Returns:

Name

Return type:

str

Usage Example:

meta_dog = sly.TagMeta('dog', sly.TagValueType.ANY_STRING)
tag_dog = sly.Tag(meta_dog, value="Husky")

print(tag_dog.name)
# Output: "dog"

property value : str¶

Tag value. Return type depends on TagValueType. Date tag values are returned as ISO datetime strings.

Returns:

Tag value

Return type:

str, int or float or None

Usage Example:

meta_dog = sly.TagMeta('dog', sly.TagValueType.ANY_STRING)
tag_dog = sly.Tag(meta_dog, value="Husky")

meta_age = sly.TagMeta('age', sly.TagValueType.ANY_NUMBER)
tag_age = sly.Tag(meta_age, value=9)

colors = ["Black", "White", "Golden", "Brown"]
meta_color = sly.TagMeta('coat color', sly.TagValueType.ONEOF_STRING, possible_values=colors)
tag_color = sly.Tag(meta_color, value="White")

meta_date = sly.TagMeta('reviewed_at', sly.TagValueType.DATE)
tag_date = sly.Tag(meta_date, value="2026-04-23T15:15:48")

type(tag_dog.value)   # 'str'
type(tag_age.value)   # 'int'
type(tag_color.value) # 'str'
type(tag_date.value)  # 'str'