R: Parse casting formulae.

parse_formula {reshape2} | R Documentation

## Parse casting formulae.

### Description

There are a two ways to specify a casting formula: either as a string, or a list of quoted variables. This function converts the former to the latter.

### Usage

    parse_formula(formula = "...  ~ variable", varnames, value.var = "value")

### Arguments

`formula` | formula to parse
`varnames` | names of all variables in data
`value.var` | name of variable containing values

### Details

Casting formulas separate dimensions with `~` and variables within a dimension with `+` or `*`. `.` can be used as a placeholder, and `...` represents all other variables not otherwise used.

### Examples

    reshape2:::parse_formula("a + ...", letters[1:6])
    reshape2:::parse_formula("a ~ b + d")
    reshape2:::parse_formula("a + b ~ c ~ .")

[Package reshape2 version 1.4.3 Index]