merge_list {StratigrapheR}

Method for merging lists by name

Description

This is a method that merges the contents of lists based on the name of the elements. In the case of identical names, the order of the lists determines which element is kept.

Usage

merge_list(l1, l2, ...)

Arguments

l1

the first list.

l2

the list which will supply additional elements to l1 that are not already there by name.

...

additionnal lists, that bring elements if they are not existing by name in the ones before.

Details

if a name appears more than once in a list, only the first one will be kept. This is particularly useful if you want to still be able to provide whichever argument you want to a function inside another function. See the advanced use in the examples to see how to do it.

Value

A merged list of all lists provided, each element (determined by its name) appearing only once.

See Also

homogenise provides a general way of dealing with function arguments.

To get a better understanding of how to deal with function arguements, go see ?do.call and ?list

Examples

# Simple use

a <- list(lty = c(2,4), mar = 4, plot = TRUE)
b <- list(mar = "hype",lty = "hype",  pink = TRUE)
d <- list(lty = FALSE, pink = "Yikes", mar = "ldkfj", test = "Successful")

merge_list(a,b,d)

# Advanced use

# We will plot points with different parameters for each lithology (see also
# the example in ?in.lim)

advanced.ex <- function(line.args = list(lty = 3, col = "grey"),
                        all = list(pch = 21, cex = 2),
                        chert = list(bg = "white"),
                        limestone = list(bg = "black"),
                        shale = list(bg = "red"),
                        main = "")
{

  # Preparation of plot and necessary data frames

  plot(proxy.example.litho$ms, proxy.example.litho$dt, type = "n",
       xlim = c(-2*10^-8, 8*10^-8), main = main)

  shale.df <- subset(proxy.example.litho, proxy.example.litho$litho == "S")
  limestone.df <- subset(proxy.example.litho, proxy.example.litho$litho == "L")
  chert.df <- subset(proxy.example.litho, proxy.example.litho$litho == "C")

  # Important part:

  # We use the do.call function, which calls a given function and provides
  # its arguments via a list. It is that list that is created by merge list.
  # for the lines function, we provide x and y coordinates, a personalised
  # list of arguments (line), and the default parameters. In this order the
  # personalised arguments override the default ones, but the latter are used
  # in the absence of personalised arguments

  line.args <- merge_list(list(x = proxy.example.litho$ms,
                               y = proxy.example.litho$dt),
                          line.args, # personalised list of arguments
                          list(lty = 3, col = "grey") # default parameters
  )

  do.call(lines, args = line.args)

  # Same procedure for the points of each lithology, but we add an 'all'
  # argument that applies for each point

  chert.args <- merge_list(list(x = chert.df$ms,
                                y = chert.df$dt), # Coordinates
                           chert, # Personalised arguments for cherts
                           all,   # Personalised arguments for all points
                           list(bg = "red"),       # Default arguments
                           list(pch = 21, cex = 2) # Default arguments
  )

  limestone.args <- merge_list(list(x = limestone.df$ms,
                                    y = limestone.df$dt),
                               limestone, all,
                               list(bg = "red"), list(pch = 21, cex = 2))

  shale.args <- merge_list(list(x = shale.df$ms, y = shale.df$dt),
                           shale, all,
                           list(bg = "red"), list(pch = 21, cex = 2))

  do.call(points, args = chert.args)
  do.call(points, args = limestone.args)
  do.call(points, args = shale.args)

}

omfrow <- par()$mfrow

par(mfrow = c(1,3))

advanced.ex(main = "Default")

advanced.ex(main = "Change line and all",
            line.args = list(lty = 1),
            all = list(pch = 22))

advanced.ex(main = "Personalise more",
           line.args = list(lty = 1, col = "black"),
            all = list(pch = 22),
            shale = list(pch = 4))

par(mfrow = omfrow)