eply {eply}

Function eply

Description

Apply a function over a data frame of quoted expressions. Parallel execution is available using the .split and .tasks arguments.

Usage

eply(.fun, .expr, .with = parent.frame())

Arguments

.fun

function to evaluate.

.expr

data frame of quoted expressions. Column names must contain the argument names of .fun.

.with

list, data frame, or environment with the data accessible to .expr

Details

.fun is a function, and .expr is a data frame. In .expr, each row stands for a single call to .fun, and each column stands for an argument. Each element is a quoted expression that uses the data in .with during evaluation. When eply is called on each row, the expressions are evaluated on .with, and the results are given to .fun as function arguments. The column names of .expr must contain the argument names of .fun. With .tasks and .split, Mac and Linux users can distribute the work over multiple parallel tasks. See the vignette for an example (vignette("eply")).

Value

a list or vector of return values of .fun.

See Also

evals, help_eply

Examples

# Get an example data frame of commands that evaluate to function arguments.
.expr <- example.expr()
.fun <- example.fun # Get an example collection of functions.
# Get an example list of supporting data. Could be an environment.
.with <- example.with()
# Row-by-row, evaluate the code in .expr and feed the results to the function.
eply(.fun = .fun, .expr = .expr, .with = .with)