R/utils.R

In lampoverde/Der: Derivatives and Structured Products

perf<-function(x0, xT){xT/x0}
rend<-function(x0, xT){xT/x0-1}

logret<-function(x){log(tail(x,-1)/head(x,-1))}


basket<-function(x,dim=c(1,3), f, ...){apply(x, dim, f, ...)}



# Fanno perdere 10% tempo (usare direttamente head(x,1) è come usare first e last )
#first<-function(x) head(x, 1)
#last<-function(x) tail(x, 1)

# Questo è come usare direttamente x[1]...
first<-function(x) x[1]
last<-function(x) x[length(x)]

# tail e' piu' generico, funziona con array e matrici


at <- function (x, pos) {
    UseMethod("at", x)
}
at.numeric<-function(x,pos){x[pos]}
at.matrix<-function(x,pos){x[pos,]}



#runApp('inst/shiny-examples/HelloShiny/')

runExample <- function(example) {
  # locate all the shiny app examples that exist
  validExamples <- list.files(system.file("shiny-examples", package = "DeR"))
  
  validExamplesMsg <-
    paste0(
      "Valid examples are: '",
      paste(validExamples, collapse = "', '"),
      "'")
  
  # if an invalid example is given, throw an error
  if (missing(example) || !nzchar(example) ||
      !example %in% validExamples) {
    stop(
      'Please run `runExample()` with a valid example app as an argument.n',
      validExamplesMsg,
      call. = FALSE)
  }
  
  # find and launch the app
  appDir <- system.file("shiny-examples", example, package = "mypackage")
  shiny::runApp(appDir, display.mode = "normal")
}