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This page covers clearml-data, ClearML's file-based data management solution. See Hyper-Datasets for ClearML's advanced queryable dataset management solution.

Datasets can be created, modified, and managed with ClearML Data's python interface. The following page provides an overview for using the most basic methods of the Dataset class. See the Dataset reference page for a complete list of available methods.

Import the Dataset class, and let's get started!

from clearml import Dataset

Creating Datasets#

ClearML Data supports multiple ways to create datasets programmatically, which provides for a variety of use-cases:

  • Dataset.create() - Create a new dataset. Parent datasets can be specified, from which the new dataset will inherit its data
  • Dataset.squash() - Generate a new dataset from by squashing together a set of related datasets


Use the Dataset.create class method to create a dataset.

Creating datasets programmatically is especially helpful when preprocessing the data so that the preprocessing code and the resulting dataset are saved in a single task (see use_current_task parameter in Dataset.create).

# Preprocessing code here
dataset = Dataset.create(
dataset_name='dataset name',
dataset_project='dataset project',
parent_datasets=[PARENT_DS_ID_1, PARENT_DS_ID_2]
Locating Dataset ID

To locate a dataset's ID, go to the dataset task's info panel in the WebApp. In the top of the panel, to the right of the dataset task name, click ID and the dataset ID appears

The created dataset inherits the content of the parent_datasets. When multiple dataset parents are listed, they are merged in order of specification. Each parent overrides any overlapping files from a previous parent dataset.


To improve deep dataset DAG storage and speed, dataset squashing was introduced. The Dataset.squash class method generates a new dataset by squashing a set of dataset versions, and merging down all changes introduced in their lineage DAG, creating a new, flat, independent version.

The datasets being squashed into a single dataset can be specified by their IDs or by project & name pairs.

# option 1 - list dataset IDs
squashed_dataset_1 = Dataset.squash(
dataset_name='squashed dataset\'s name',
dataset_ids=[DS1_ID, DS2_ID, DS3_ID]
# option 2 - list project and dataset pairs
squashed_dataset_2 = Dataset.squash(
dataset_name='squashed dataset 2',
dataset_project_name_pairs=[('dataset1 project', 'dataset1 name'),
('dataset2 project', 'dataset2 name')]

In addition, the target storage location for the squashed dataset can be specified using the output_url parameter of the Dataset.squash method.

Accessing Datasets#

Once a dataset has been created and uploaded to a server, the dataset can be accessed programmatically from anywhere.

Use the Dataset.get class method to access a specific Dataset object, either with the dataset's ID or with its project and name. If only a project name or tag is provided, the method returns the most recent dataset in the specified project, or the most recent dataset with the specified tag.

Once a specific dataset object has been obtained, get a local copy of the dataset using one of the following options:

  • Dataset.get_local_copy() - get a read-only local copy of an entire dataset. This method returns a path to the dataset in local cache (downloading the dataset if it is not already in cache).
  • Dataset.get_mutable_local_copy() - get a writable local copy of an entire dataset. This method downloads the dataset to a specific folder (non-cached), specified with the target_folder parameter. If the specified folder already has contents, specify whether to overwrite its contents with the dataset contents, using the overwrite parameter.

Modifying Datasets#

Once a dataset has been created, its contents can be modified and replaced. When your data is changed, you can add updated files or remove unnecessary files.


To add files or folders into the current dataset, use the Dataset.add_files method. If a file is already in a dataset, but it has been modified, it can be added again, and ClearML will upload the file diff.

dataset = Dataset.create()

There is an option to add a set of files based on wildcard matching of a single string or a list of strings, using the wildcard parameter. Specify whether to match the wildcard files recursively using the recursive parameter.

For example:



To remove files from a current dataset, use the Dataset.remove_files method. Input the path to the folder or file to be removed in the dataset_path parameter. The path is relative to the dataset.

There is also an option to input a wildcard into dataset_path in order to remove a set of files matching the wildcard. Set the recursive parameter to True in order to match all wildcard files recursively

For example:

dataset.remove_files(dataset_path="*.csv", recursive=True)

Uploading Files#

To upload the dataset files to network storage, use the Dataset.upload method. Use the output_url parameter to specify storage target, such as S3 / GS / Azure (e.g. s3://bucket/data, gs://bucket/data, azure://bucket/data , /mnt/share/data). By default, the dataset uploads to ClearML's file server.

Dataset files must be uploaded before a dataset is finalized.

Finalizing a Dataset#

Use the Dataset.finalize method to close the current dataset. This marks the dataset task as Completed, at which point, the dataset can no longer be modified.

Before closing a dataset, its files must first be uploaded.

Syncing Local Storage#

Use the Dataset.sync_folder method in order to update a dataset according to a specific folder's content changes. Specify the folder to sync with the local_path parameter (the method assumes all files within the folder and recursive).

This method is useful in the case where there's a single point of truth, either a local or network folder, that gets updated periodically. The folder changes will be reflected in a new dataset version. This method saves time since you don't have to manually update (add / remove) files in a dataset.