# Channels and units

Inspect channel metadata, search tagged logs, and manage measurement units.

## API Reference

Import from `nominal.core`.

Classes

| [`BatchAddChannelsResult`](https://dev.nominal.io/python/ref/generated/nominal.core.BatchAddChannelsResult.md#nominal.core.BatchAddChannelsResult "nominal.core.BatchAddChannelsResult") | Results of a batch channel create or update, including unresolved requests. |
| --- | --- |
| [`Channel`](https://dev.nominal.io/python/ref/generated/nominal.core.Channel.md#nominal.core.Channel "nominal.core.Channel") | Metadata for working with channels. |
| [`CreateChannelRequest`](https://dev.nominal.io/python/ref/generated/nominal.core.CreateChannelRequest.md#nominal.core.CreateChannelRequest "nominal.core.CreateChannelRequest") | Channel metadata to create or update through a dataset's batch methods. |
| [`Unit`](https://dev.nominal.io/python/ref/generated/nominal.core.Unit.md#nominal.core.Unit "nominal.core.Unit") | Combination of the name and symbol of a unit within the supported systems of measurement. |

Enumerations

| [`ChannelDataType`](https://dev.nominal.io/python/ref/generated/nominal.core.ChannelDataType.md#nominal.core.ChannelDataType "nominal.core.ChannelDataType") | The type of values stored in a channel. |
| --- | --- |

Functions

| [`filter_channels_with_data`](https://dev.nominal.io/python/ref/generated/nominal.core.filter_channels_with_data.md#nominal.core.filter_channels_with_data "nominal.core.filter_channels_with_data") | Yield channels that have data in the given time range, optionally filtered by tags. |
| --- | --- |

Type aliases

| [`UnitLike`](https://dev.nominal.io/python/ref/core/channels-and-units.md#nominal.core.UnitLike "nominal.core.UnitLike") | [`Unit`](https://dev.nominal.io/python/ref/generated/nominal.core.Unit.md#nominal.core.Unit "nominal.core.unit.Unit") | [`str`](https://docs.python.org/3/builtins/stdtypes.html#str "(in Python v3.15)") | [`None`](https://docs.python.org/3/builtins/constants.html#None "(in Python v3.15)") |
| --- | --- |