R: Evaluate an R expression with options set temporarily

withOptions {R.utils} | R Documentation

## Evaluate an R expression with options set temporarily

### Description

Evaluate an R expression with options set temporarily.

### Usage

    withOptions(expr, ..., args=list(), substitute=TRUE, envir=parent.frame())

### Arguments

`expr` | The R expression to be evaluated.
`...` | Named options to be used.
`args` | (optional) Additional named options specified as a named `list`.
`substitute` | If `TRUE`, argument `expr` is `substitute()`:ed, otherwise not.
`envir` | The `environment` in which the expression should be evaluated.

### Details

Upon exit (also on errors), this function will reset all options to the state of options available upon entry. This means any options modified but also those added when evaluating `expr` will also be undone upon exit.

### Value

Returns the results of the expression evaluated.

### Author(s)

Henrik Bengtsson

### See Also

Internally, `eval`() is used to evaluate the expression. and `options`() to set options.

### Examples

    print(pi)

    # Same, i.e. using default
    withOptions({
      print(pi)
    })

    # Printing with two digits
    withOptions({
      print(pi)
    }, digits=2)

    # Printing with two digits then with three more
    withOptions({
      print(pi)
      withOptions({
        print(pi)
      }, digits=getOption("digits")+3)
    }, digits=2)

    # Still printing with the default
    print(pi)

[Package R.utils version 2.7.0 Index]