Download QMNIST — download_qmnist • snedata

Download QMNIST database of handwritten digits. This is the same as the MNIST digits, but with an extended test dataset of 60,000 digits.

Usage

download_qmnist(
  base_url = qmnist_url,
  verbose = FALSE,
  as = c("data.frame", "list"),
  timeout = 1800
)

Format

A data frame with 785 variables:

px1, px2, px3 ... px784: Integer pixel value, from 0 (white) to 255 (black).
Label: The digit represented by the image, in the range 0-9.

Pixels are organized row-wise. The Label variable is stored as a factor.

There are 120,000 digits in the data set. The first 60,000 are the training set, as found in the qmnist-train-images-idx3-ubyte.gz file. The remaining 60,000 are the test set, from the qmnist-test-images-idx3-ubyte.gz file.

Items in the dataset can be visualized with show_mnist_digit().

For more information see https://github.com/facebookresearch/qmnist.

Arguments

base_url: Base URL that the QMNIST files are located at.
verbose: If TRUE, then download progress will be logged as a message.
as: Return format. Use "data.frame" for the original data frame shape, or "list" for the canonical image result described in download_mnist().
timeout: Minimum download timeout in seconds. The default is 30 minutes; a larger existing global R timeout is preserved.

Value

If as = "data.frame", a data frame containing the QMNIST digits. If as = "list", a canonical image result. Its meta includes all eight QMNIST extended-label fields in addition to id, split, and label.

Details

Downloads the image and label files for the training and test datasets from https://github.com/facebookresearch/qmnist and converts them to a data frame or canonical list result.

References

Yadav, C., & Bottou, L. (2019, May). Cold Case: The Lost MNIST Digits arXiv preprint arXiv:1905.10498. https://github.com/facebookresearch/qmnist

Examples

if (FALSE) { # \dontrun{
# download the QMNIST data set
qmnist <- download_qmnist()

# first 60,000 instances are the training set
qmnist_train <- head(qmnist, 60000)
# the remaining 60,000 are the test set
qmnist_test <- tail(qmnist, 60000)
} # }