datasets

This module has the necessary functions to be able to download several useful datasets that we might be interested in using in our models.

class URLs[source]

URLs()

This contains all the datasets' and models' URLs, and some classmethods to help use them - you don't create objects of this class. The supported datasets are (with their calling name): S3_NLP, S3_COCO, MNIST_SAMPLE, MNIST_TINY, IMDB_SAMPLE, ADULT_SAMPLE, ML_SAMPLE, PLANET_SAMPLE, CIFAR, PETS, MNIST. To get details on the datasets you can see the fast.ai datasets webpage. Datasets with SAMPLE in their name are subsets of the original datasets. In the case of MNIST, we also have a TINY dataset which is even smaller than MNIST_SAMPLE.

Models is now limited to WT103 but you can expect more in the future!

URLs.MNIST_SAMPLE
'http://files.fast.ai/data/examples/mnist_sample'

Downloading Data

For the rest of the datasets you will need to download them with untar_data or download_data. untar_data will decompress the data file and download it while download_data will just download and save the compressed file in .tgz format.

By default, data will be downloaded to ~/.fastai/data folder.
Configure the default data_path by editing ~/.fastai/config.yml.

untar_data[source]

untar_data(url:str, fname:PathOrStr=None, dest:PathOrStr=None, data=True)

Download url if it doesn't exist to fname and un-tgz to folder dest

untar_data(URLs.PLANET_SAMPLE)
PosixPath('/home/jhoward/.fastai/data/planet_sample')

download_data[source]

download_data(url:str, fname:PathOrStr=None)

Download url to destination fname

Note: If the data file already exists in a data directory inside the notebook, that data file will be used instead of ~/.fasta/data. Paths are resolved by calling the function datapath4file - which checks if data exists locally (data/) first, before downloading to ~/.fastai/data home directory.

Example:

download_data(URLs.PLANET_SAMPLE)
PosixPath('/home/jhoward/.fastai/data/planet_sample.tgz')

datapath4file[source]

datapath4file(filename)

Returns URLs.DATA path if file exists. Otherwise returns config path

All the downloading functions use this to decide where to put the tgz and expanded folder. If filename already exists in a data directory in the same place as the calling notebook/script, that is used as the parent directly, otherwise ~/.fastai/config.yml is read to see what path to use, which defaults to ~/.fastai/data is used. To override this default, simply modify the value in your ~/.fastai/config.yml:

data_path: ~/.fastai/data

class Config[source]

Config()

Creates a default config file at ~/.fastai/config.yml

You probably won't need to use this yourself - it's used by URLs.datapath4file.