Version:	4.2.3
Title:	Interface to 'Altair'
Description:	Interface to 'Altair' https://altair-viz.github.io, which itself is a 'Python' interface to 'Vega-Lite' https://vega.github.io/vega-lite/. This package uses the 'Reticulate' framework https://rstudio.github.io/reticulate/ to manage the interface between R and 'Python'.
SystemRequirements:	Python (>= 3.6.0), (Python) Altair (>= 4.2.0), vega_datasets (>= 0.9.0). To use image functions for MacOS: X11
License:	MIT + file LICENSE
Encoding:	UTF-8
ByteCompile:	true
URL:	https://github.com/vegawidget/altair
BugReports:	https://github.com/vegawidget/altair/issues
Imports:	reticulate (≥ 1.23), htmlwidgets, assertthat, magrittr, utils, vegawidget (≥ 0.4.1), repr
Suggests:	httr, rprojroot, purrr, readr, knitr, rmarkdown, tibble, listviewer (≥ 2.0.0), testthat, pryr, stringr, tidyr, dplyr, pkgdown, V8, rsvg, png, fs
RoxygenNote:	7.2.3
NeedsCompilation:	no
Packaged:	2023-09-04 01:22:53 UTC; ijlyttle
Author:	Ian Lyttle [aut, cre], Haley Jeppson [aut], Altair Developers [aut], Alicia Schep [ctb], Jake Vanderplas [ctb] (Altair library), Brian Granger [ctb] (Altair library)
Maintainer:	Ian Lyttle <ijlyttle@me.com>
Repository:	CRAN
Date/Publication:	2023-09-04 03:50:02 UTC

altair: Create and embed Vega-Lite charts using the Altair Python package

Description

The goal of altair is to help you build Vega-Lite visualizations. Using the reticulate package, it provides an interface to the Altair Python package.

Details

In this documentation, the capitalized word Altair shall refer to the Python package; the lower-case word altair shall refer to this R package.

Author(s)

Maintainer: Ian Lyttle ijlyttle@me.com (ORCID)

Authors:

• Haley Jeppson hjeppson@iastate.edu

• Altair Developers

Other contributors:

• Alicia Schep aschep@gmail.com (ORCID) [contributor]

• Jake Vanderplas (Altair library) [contributor]

• Brian Granger (Altair library) [contributor]

See Also

altair pkgdown website, Altair Python package, Vega-Lite

Pipe operator

Description

See magrittr::%>% for details.

Usage

lhs %>% rhs

Mark character strings as literal JavaScript code

Description

This function is re-exported from the htmlwidgets package. See htmlwidgets::JS() for more details.

Usage

JS(...)

See Also

htmlwidgets::JS()

Altair object

Description

Uses the reticulate framework to access the Altair API.

Usage

alt

Format

An object of class python.builtin.module (inherits from python.builtin.object) of length 1.

Details

The Altair Python package is exposed through the alt object. You can create and add to chart using its methods and classes, as outlined in the Altair Python documentation.

In this package, use the $ operator wherever you see the . operator used in Python.

See Also

Altair Python documentation, altair: Field Guide to Python Issues

Examples

if (interactive()) {
  vega_data <- import_vega_data()

  plot_basic <-
    alt$Chart(vega_data$cars())$
    encode(
      x = "Miles_per_Gallon:Q",
      y = "Horsepower:Q",
      color = "Origin:N"
    )$
    mark_point()

   plot_basic
}

Altair plot concatenation

Description

Altair plots can be concatenated using the following operators: +, |, and &

Usage

## S3 method for class 'altair.vegalite.v4.api.TopLevelMixin'
e1 | e2

## S3 method for class 'altair.vegalite.v4.api.TopLevelMixin'
e1 + e2

## S3 method for class 'altair.vegalite.v4.api.TopLevelMixin'
e1 & e2

Arguments

Value

Compound Altair chart object

Examples

if (interactive()){

  # Examples using the beaver1 and beaver2 body temperature data sets
  # Layering Charts
  base <- alt$Chart(beaver1)$encode(
    x = alt$X('time'),
    y = alt$Y('temp', scale = alt$Scale(zero = FALSE))
  )

  scatter_plot <- base$mark_point()
  line_plot <- base$mark_line()

  combined_plot <- scatter_plot + line_plot

  # Horizontal Concatenation
  base2 <- alt$Chart(beaver2)$
    encode(
      x = alt$X("time"),
      y = alt$Y("temp", scale = alt$Scale(zero = FALSE))
    )

  scatter_plot2 <- base2$mark_point()
  line_plot2 <- base2$mark_line()

  combined_plot <-
    (scatter_plot + line_plot)$
    properties(title = "Beaver 1", width = 200)

  combined_plot2 <-
    (scatter_plot2 + line_plot2)$
    properties(title = "Beaver 2", width = 200)

  hconcat_plot <- combined_plot | combined_plot2

  # Vertical Concatenation
  vconcat_plot <- combined_plot & combined_plot2

}

Installed versions of Altair, Vega, etc.

Description

Returns a named list of version tags for Altair, Vega, Vega-Lite, and Vega-Embed

Usage

altair_version()

Value

named list of version tags

Examples

if (interactive()) {
  altair_version()
}

Create Altair chart from vegaspec

Description

Create Altair chart from vegaspec

Usage

as_chart(spec)

Arguments

Value

altair object

Examples

  if (interactive()) {
    as_chart(vegawidget::spec_mtcars)
  }

Coerce to vegaspec

Description

See vegawidget::as_vegaspec for details.

Usage

## S3 method for class 'altair.vegalite.v4.api.TopLevelMixin'
as_vegaspec(spec, ...)

Arguments

Check the Altair installation

Description

Provides feedback on any differences between your installed version of Altair and the version this package supports.

Usage

check_altair(quiet = FALSE)

Arguments

Details

If the supported Altair version is different from your installed version, this function will act according to where the difference in the version numbers:

• major version leads to an error

• minor version leads to a warning

• patch version leads to a message

If there is no difference:

• quiet = FALSE, success message showing version-numbers

• quiet = TRUE, no message

To install the supported version into a Python environment called "r-reticulate", use install_altair().

Value

invisible NULL, called for side-effects

See Also

reticulate::py_config(), install_altair(), altair_version()

Examples

## Not run: 
  # not run because it requires Python
  check_altair()

## End(Not run)

Create or write image

Description

See vegawidget::image for details.

Import Vega datasets

Description

Lets you access Vega datasets.

Usage

import_vega_data()

Details

Returns the data object in the Python package vega-datasets. In the documentation for this package, the convention is to assign this object to the name vega_data.

Value

An S3 object of class vega_datasets.core.DataLoader

See Also

Vega datasets documentation

Examples

if (interactive()) {
  vega_data <- import_vega_data()

  # To list available datasets
  print(vega_data$list_datasets())

  # When accessing a dataset, substitute any "-" in the name with a "_"
  print(head(vega_data$sf_temps()))

  # Metadata are available for each dataset:
  print(vega_data$anscombe$references)
  print(vega_data$anscombe$description)
  print(vega_data$anscombe$url)

  # For local datasets, local path is available
  print(vega_data$sf_temps$filepath)
}

Install Altair Python package

Description

This function wraps installation functions from reticulate to install the Python packages altair and vega_datasets.

Usage

install_altair(
  method = c("conda", "virtualenv"),
  envname = "r-reticulate",
  version = getOption("altair.python.version"),
  ...
)

Arguments

Details

This package uses the reticulate package to make an interface with the Altair Python package. To promote consistency in usage of reticulate among different R packages, it is recommended to use a common Python environment, called "r-reticulate".

Depending on your setup, you can create this environment using reticulate::conda_create() or reticulate::virtualenv_create(), as described in this reticulate article, or in this package's Installation article.

Value

invisible NULL, called for side-effects

See Also

altiar: Installation, reticulate: Using reticulate in an R Package, reticulate: Installing Python Packages

Examples

## Not run: 
  # not run because it requires Python
  install_altair()

## End(Not run)

Knit-print method

Description

See vegawidget::knit_print.vegaspec for details, particularly on additional packages that may have to be installed.

Usage

knit_print.altair.vegalite.v4.api.TopLevelMixin(spec, ..., options = NULL)

Arguments

Render shiny-output for vegawidget

Description

Deprecated, please use vegawidget::renderVegawidget.

Usage

renderVegawidget(expr, env = parent.frame(), quoted = FALSE)

Arguments

MIME method for text

Description

MIME method for text

Usage

## S3 method for class 'altair.vegalite.v4.api.TopLevelMixin'
repr_text(obj, ...)

Arguments

Value

character

MIME method for chart rendering

Description

MIME method for chart rendering

Usage

## S3 method for class 'altair.vegalite.v4.api.TopLevelMixin'
repr_vegalite4(obj, ...)

Arguments

Value

list, reflecting JSON spec

Vega embed options

Description

See vegawidget::vega_embed for details.

Create a Vega/Vega-Lite htmlwidget

Description

See vegawidget::vegawidget for details.

Shiny-output for vegawidget

Description

Deprecated, please use vegawidget::vegawidgetOutput.

Usage

vegawidgetOutput(outputId, width = "auto", height = "auto")

Arguments

Coerce vegaspec to JSON

Description

Deprecated, please use vegawidget::vw_as_json.

Usage

vw_as_json(spec, pretty = TRUE)

Arguments

Value

jsonlite::json object

Set base URL

Description

See vegawidget::vw_set_base_url for details.