# Data types gel-python automatically converts Gel types to the corresponding Python types and vice versa. The table below shows the correspondence between Gel and Python types. | Gel Type | Python Type | | ----------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `Set` | [`gel.Set`](https://docs.geldata.com/reference/using/python/api/types.md#gel.Set) | | `array` | [`gel.Array`](https://docs.geldata.com/reference/using/python/api/types.md#gel.Array) | | `anytuple` | [`gel.Tuple`](https://docs.geldata.com/reference/using/python/api/types.md#gel.Tuple) or [`gel.NamedTuple`](https://docs.geldata.com/reference/using/python/api/types.md#gel.NamedTuple) | | `anyenum` | [`gel.EnumValue`](https://docs.geldata.com/reference/using/python/api/types.md#gel.EnumValue) | | `Object` | [`gel.Object`](https://docs.geldata.com/reference/using/python/api/types.md#gel.Object) | | `bool` | [`bool`](https://docs.python.org/3/library/functions.html#bool) | | `bytes` | [`bytes`](https://docs.python.org/3/library/stdtypes.html#bytes) | | `str` | [`str`](https://docs.python.org/3/library/stdtypes.html#str) | | `cal::local_date` | [`datetime.date`](https://docs.python.org/3/library/datetime.html#datetime.date) | | `cal::local_time` | offset-naive [`datetime.time `](https://docs.python.org/3/library/datetime.html#datetime.time) | | `cal::local_datetime` | offset-naive [`datetime.datetime `](https://docs.python.org/3/library/datetime.html#datetime.datetime) | | `cal::relative_duration` | [`gel.RelativeDuration`](https://docs.geldata.com/reference/using/python/api/types.md#gel.RelativeDuration) | | `cal::date_duration` | [`gel.DateDuration`](https://docs.geldata.com/reference/using/python/api/types.md#gel.DateDuration) | | `datetime` | offset-aware [`datetime.datetime `](https://docs.python.org/3/library/datetime.html#datetime.datetime) | | `duration` | [`datetime.timedelta `](https://docs.python.org/3/library/datetime.html#datetime.timedelta) | | `float32`, `float64` | [`float`](https://docs.python.org/3/library/functions.html#float) | | `int16`, `int32`, `int64`, `bigint` | [`int`](https://docs.python.org/3/library/functions.html#int) | | `decimal` | [`Decimal`](https://docs.python.org/3/library/decimal.html#decimal.Decimal) | | `json` | [`str`](https://docs.python.org/3/library/stdtypes.html#str) | | `uuid` | [`uuid.UUID`](https://docs.python.org/3/library/uuid.html#uuid.UUID) | > Note: Inexact single-precision `float` values may have a different representation when decoded into a Python float. This is inherent to the implementation of limited-precision floating point types. If you need the decimal representation to match, cast the expression to `float64` or `decimal` in your query. ## Sets ## Class: Set ```py Set ``` This is [`list`](https://docs.python.org/3/library/stdtypes.html#list) since version 1.0. ## Objects ## Class: Object ```py Object ``` An immutable representation of an object instance returned from a query. `gel.Object` instances are dataclass-compatible since version 1.0, for example, `dataclasses.is_dataclass()` will return `True`, and `dataclasses.asdict()` will work on `gel.Object` instances. `gel.Object.__hash__` is just `object.__hash__` in version 1.0. Similarly, `==` is equivalent to the `is` operator comparing `gel.Object` instances, and `<`, `<=`, `>`, `>=` are not allowed on `gel.Object` instances. The value of an object property or a link can be accessed through a corresponding attribute: ```pycon >>> import gel >>> client = gel.create_client() >>> r = client.query_single(''' ... SELECT schema::ObjectType {name} ... FILTER .name = 'std::Object' ... LIMIT 1''') >>> r Object{name := 'std::Object'} >>> r.name 'std::Object' ``` ## Describe: obj[linkname] ``` obj[linkname] ``` Return a [`gel.Link`](https://docs.geldata.com/reference/using/python/api/types.md#gel.Link) or a [`gel.LinkSet`](https://docs.geldata.com/reference/using/python/api/types.md#gel.LinkSet) instance representing the instance(s) of link *linkname* associated with *obj*. Example: ```pycon >>> import gel >>> client = gel.create_client() >>> r = client.query_single(''' ... SELECT schema::Property {name, annotations: {name, @value}} ... FILTER .name = 'listen_port' ... AND .source.name = 'cfg::Config' ... LIMIT 1''') >>> r Object { name: 'listen_port', annotations: { Object { name: 'cfg::system', @value: 'true' } } } >>> r['annotations'] LinkSet(name='annotations') >>> l = list(r['annotations])[0] >>> l.value 'true' ``` ## Links ## Class: Link ```py Link ``` An immutable representation of an object link. Links are created when [`gel.Object`](https://docs.geldata.com/reference/using/python/api/types.md#gel.Object) is accessed via a `[]` operator. Using Link objects explicitly is useful for accessing link properties. ## Class: LinkSet ```py LinkSet ``` An immutable representation of a set of Links. LinkSets are created when a multi link on [`gel.Object`](https://docs.geldata.com/reference/using/python/api/types.md#gel.Object) is accessed via a `[]` operator. ## Tuples ## Class: Tuple ```py Tuple ``` This is [`tuple`](https://docs.python.org/3/library/stdtypes.html#tuple) since version 1.0. ## Named Tuples ## Class: NamedTuple ```py NamedTuple ``` An immutable value representing a Gel named tuple value. `gel.NamedTuple` is a subclass of [`tuple`](https://docs.python.org/3/library/stdtypes.html#tuple) and is duck-type compatible with `collections.namedtuple` since version 1.0. Instances of `gel.NamedTuple` generally behave similarly to [`namedtuple`](https://docs.python.org/3/library/collections.html#collections.namedtuple): ```pycon >>> import gel >>> client = gel.create_client() >>> r = client.query_single('''SELECT (a := 1, b := 'a', c := [3])''') >>> r (a := 1, b := 'a', c := [3]) >>> r.b 'a' >>> r[0] 1 >>> r == (1, 'a', [3]) True >>> r._fields ('a', 'b', 'c') ``` ## Arrays ## Class: Array ```py Array ``` This is [`list`](https://docs.python.org/3/library/stdtypes.html#list) since version 1.0. ## RelativeDuration ## Class: RelativeDuration ```py RelativeDuration ``` An immutable value representing a Gel `cal::relative_duration` value. ```pycon >>> import gel >>> client = gel.create_client() >>> r = client.query_single('''SELECT "1 year 2 days 3 seconds"''') >>> r >>> r.months 12 >>> r.days 2 >>> r.microseconds 3000000 ``` ## DateDuration ## Class: DateDuration ```py DateDuration ``` An immutable value representing a Gel `cal::date_duration` value. ```pycon >>> import gel >>> client = gel.create_client() >>> r = client.query_single('''SELECT "1 year 2 days"''') >>> r >>> r.months 12 >>> r.days 2 ``` ## EnumValue ## Class: EnumValue ```py EnumValue ``` An immutable value representing a Gel enum value. Since version 1.0, `gel.EnumValue` is a subclass of [`enum.Enum`](https://docs.python.org/3/library/enum.html#enum.Enum). Actual enum values are instances of ad-hoc enum classes created by the codecs to represent the actual members defined in your Gel schema. ```pycon >>> import gel >>> client = gel.create_client() >>> r = client.query_single("""SELECT 'red'""") >>> r >>> str(r) 'red' >>> r.value # added in 1.0 'red' >>> r.name # added in 1.0, simply str.upper() of r.value 'RED' ```