How to use aliases when creating a Table

An alias is simply a text string that represents a part of a path to an object. Aliases can help you share 3LC runs and Tables across machines without needing to move large amounts of bulk data. For details about aliases, please visit the Sharing 3LC Tables and Runs page. If you want to incorporate aliases into your 3LC Tables, you need to set up the aliases before you create the Tables.

You can set up aliases in the config.yaml file, which is located at %LocalAppData%\3LC\3LC\config.yaml for Windows. For other Operating Systems, please see the page Default File Locations. Under the aliases section in the YAML file, you set an alias like this below, assuming that the Cifar-10 data is located in C:/Users/Adam/my_data/Cifar-10-data/.

aliases:
  CIFAR10_DATA: C:/Users/Adam/my_data/Cifar-10-data/

You can also set up aliases through environment variables. Environment variables with the prefix TLC_ALIAS_ will be picked up during initialization of the tlc module. To define an alias equivalent to the example above, you might for instance run:

export TLC_ALIAS_CIFAR10_DATA="C:/Users/Adam/my_data/Cifar-10-data/"

If an image’s absolute path is C:/Users/Adam/my_data/Cifar-10-data/train/image_1.jpg, the aliased path for this image will be <CIFAR10_DATA>/train/image_1.jpg. All image URLs will be stored with the aliased paths in the 3LC Table. When you share this project with others, they need to specify where the corresponding bulk data is located on their system by setting up the same alias on their system.

Registering aliases

In addition to setting up aliases ahead of script execution, you can also register aliases programmatically. The following snippet shows how to register aliases programmatically:

import tlc

tlc.register_url_alias("CIFAR10_DATA", "C:/Users/Adam/my_data/Cifar-10-data/")

Applying aliases to paths

The following snippet shows how to apply and resolve aliases manually:

import tlc

my_path = "C:/Users/Adam/my_data/Cifar-10-data/train/image_1.jpg"
aliased_path = tlc.Url(my_path).apply_aliases()
# tlc.Url("<CIFAR10_DATA>/train/image_1.jpg")
unaliased_path = aliased_path.expand_aliases()
# tlc.Url("C:/Users/Adam/my_data/Cifar-10-data/train/image_1.jpg")