by_sim: Map a function simulation-wise
In lionel-/gsim: Gorgeous manipulations of (posterior) simulations

by_sim() is similar to apply() in that it applies a function .f to the margins of an array. by_sim() is specialised to apply the function on each simulation of a sims_array. It can be also be applied to a list of simulations, in which case .f may depend on several parameters.

by_sim(.x, .f, ..., .context = list(), .bindings = NULL)

## S3 method for class 'list'
by_sim(.x, .f, ..., .context = list(), .bindings = NULL)

## S3 method for class 'sims'
by_sim(.x, .f, ..., .context = list(), .bindings = NULL)

## S3 method for class 'sims_array'
by_sim(.x, .f, ..., .context = list(), .sims = list(),
  .bindings = NULL)

`.x`	A list of simulations arrays, or a simulations array.
`.f`	A function or an expression to be applied to each simulation.
`...`	Further arguments passed on to `.f`.
`.context`	A list or a data frame that contains additional variables used in `.f`.
`.bindings`	A named vector linking the arguments of `.f` to the names of the simulations arrays in `.x`, in case they do not match.
`.sims`	A list of simulations arrays containing additional parameters on which `.statistic` depends.