R: Use Python

use_python {reticulate} | R Documentation

## Use Python

### Description

Select the version of Python to be used by `reticulate`.

### Usage

    use_python(python, required = NULL)

    use_python_version(version, required = NULL)

    use_virtualenv(virtualenv = NULL, required = NULL)

    use_condaenv(condaenv = NULL, conda = "auto", required = NULL)

    use_miniconda(condaenv = NULL, required = NULL)

### Arguments

`python` | The path to a Python binary.
`required` | Is the requested copy of Python required? If `TRUE`, an error will be emitted if the requested copy of Python does not exist. Otherwise, the request is taken as a hint only, and scanning for other versions will still proceed.
`version` | The version of Python to use. `reticulate` will search for versions of Python as installed by the `install_python()` helper function.
`virtualenv` | Either the name of, or the path to, a Python virtual environment.
`condaenv` | The conda environment to use. This can be the name, the absolute prefix path or the absolute path to the python binary. If the name is ambiguous, the first environment is used and a warning is issued.
`conda` | The path to a `conda` executable. By default, `reticulate` will check the `PATH`, as well as other standard locations for Anaconda installations.

### Details

The `reticulate` package initializes its Python bindings lazily – that is, it does not initialize its Python bindings until an API that explicitly requires Python to be loaded is called. This allows users and package authors to request particular versions of Python by calling `use_python()` or one of the other helper functions documented in this help file.

### RETICULATE_PYTHON

The `RETICULATE_PYTHON` environment variable can also be used to control which copy of Python `reticulate` chooses to bind to. It should be set to the path to a Python interpreter, and that interpreter can either be:

- A standalone system interpreter,

- Part of a virtual environment,

- Part of a Conda environment.

When set, this will override any other requests to use a particular copy of Python. Setting this in `~/.Renviron` (or optionally, a project `.Renviron`) can be a useful way of forcing `reticulate` to use a particular version of Python.

### Caveats

Note that the requests for a particular version of Python via `use_python()` and friends only persist for the active session; they must be re-run in each new R session as appropriate.

If `use_python()` (or one of the other `use_*()` functions) are called multiple times, the most recently-requested version of Python will be used. Note that any request to `use_python()` will always be overridden by the `RETICULATE_PYTHON` environment variable, if set.

The `py_config()` function will also provide a short note describing why `reticulate` chose to select the version of Python that was ultimately activated.

[Package reticulate version 1.25 Index]