## Transform an object, e.g. a dataframe

## Usage

    transform(x, ...)

## Arguments

`x` | The object to be transformed
`...` | Further arguments of the form `tag=value`

## Description

`transform` is a generic function, which -- at least currently -- only does anything useful with dataframes. `transform.default` converts its first argument to a dataframe if possible and calls `transform.data.frame`.

The `...` arguments to `transform.data.frame` are tagged vector expressions, which are evaluated in the dataframe `x`. The tags are matched against `names(x)`, and for those that match, the value replace the corresponding variable in `x`, and the others are appended to `x`

## Value

The modified value of `x`

## Note

If some of the values are not vectors of the appropriate length, you deserve whatever you get!

## Author(s)

Peter Dalgaard

## See Also

`subset`, `list`, `data.frame`

## Examples

    data(airquality)
    transform(airquality,Ozone=-Ozone)
    transform(airquality,new=-Ozone,Temp=(Temp-32)/1.8)

    attach(airquality)
    transform(Ozone,logOzone=log(Ozone)) # marginally interesting...
    detach(airquality)

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