load_rde_var {rde}

Load data in a reproducible way that allows for exchange of code

Description

load_rde_var attempts to execute the code in load.fcn. If that succeeds, then the return value of that code is returned by load_rde_var. Otherwise, the value stored in cache is returned. cache must contain an encoded copy of the value produced by the function copy_rde_var. Optionally, you can force the use of the cached data by setting use.cache = TRUE.

Usage

load_rde_var(use.cache = FALSE, load.fcn, cache)

Arguments

use.cache

boolean to force the use of cached data

load.fcn

code to load the data from its original source

cache

a cached copy of the data

Details

This package is intended for small datasets. A copy of the data is encoded as a string (using base64 encoding, after compressing the data) and that string is copied into your code. Even though the data is compressed, the encoded string can still be quite long. If your data is more than a few hundred observations, this package probably isn't for you.

load.fcn must contain executable R code. Unless that code is a single expression, normally it would be enclosed in a pair of braces.

cache must be a string that was originally produced by copy_rde_var. See the documentation for that function for more details about the format of this string.

If the code in load.fcn fails, then a message is produced to indicate that the failure and the data encoded in cache is returned instead. This would occur if you share you code with someone who does not have access to the data that you're loading in your code.

If use.cache = TRUE, the code in load.fcn is ignored and the data is loaded from the encoded string cache. This can be useful if it takes a very long time obtain the data and you re-run your code often.

If the value produced by the code in load.fcn does not match the value encoded in cache, then a warning is produced to indicate that there is a mismatch.

Value

The data, either loaded using load.fcn, if possible, or from cache if that fails.

See Also

copy_rde_var

Examples

load_rde_var(use.cache = FALSE, {
    head(iris, 3)
  }, "
  rde1QlpoOTFBWSZTWbGO254AAKT/5P//XAAAAQAAwARIwC/n3YBAAAAwACYFAbAA7IhKIm
  lPaU3oaRqekyaDTQNPJP1MhDAaA0AAGmg0A0AaBIokNGgAAAAAANMYUzuJyxRYUJWNnsC1
  tgiccpLFvZTHhARK1KFQ1z25bNBCC+0pWKgEnGEzpxVaihSiTBL2j6RRFchjamGBFpBMwN
  bAHwgEGosCEGYBoztHPFUVjGcDz3qu9p4cb8rVyVfHmR5S3bWXfDDnTnyJDJh0iMIpionY
  lfq1FwK/IvzsuBsOmuZNGtpp7oWrW4upNNGDiL2E9T6iY2RFqabO9/r9oiN6p/YIdV1FPP
  ISLqVP4u5IpwoSFjHbc8A=
  ")