Install and Load Packages

loadPackages.R

#' Load packages and install packages that are not installed before loading
#'
#' This function allows you to check install packages then load
#' @param packages Vector of packages names to be installed
#' @param dependencies Logical. Return package dependencies?
#' @param repos Repository for install.packages()
#' @keywords install.packages
#' @keywords require
#' @keywords library 
#' @export
#' @examples 
#' loadPackages(packages=c('hi','pscl','XML','quantmod','Rcpp','foreign'))



loadPackages <- function(packages, dependencies=TRUE, repos="http://cran.rstudio.com/", ...){
  pack <- available.packages() #list of all available packages on CRAN
  #create empty vectors to be returned as a list
  loaded <- c()
  installed <- c()
  error <- c()
  for(i in 1:length(packages)){
    #if package is already installed just load it
    if (packages[i] %in% row.names(installed.packages())  == TRUE){
      
      #Load the Package
      library(packages[i], character.only=TRUE, ...)
      
      #List it with or without its dependencies
      if(dependencies==TRUE){
          loaded <- rbind(loaded,cbind(packages[i], pack[packages[i],"Depends"]))
          colnames(loaded)<-c("Package","Dependencies")
      } else {
          loaded <- rbind(loaded,packages[i])
          colnames(loaded)<-c("Package")
      }
      
      #if package is not already installed install it first checcking for error and then load it
    } else  if (packages[i] %in% row.names(installed.packages())  == FALSE){
      
      if(packages[i] %in% names(pack[,1])==FALSE){
        error <- cbind(error, packages[i])
        colnames(error)<-c("Package")
        next
      }
      
      install.packages(packages[i], repos=repos)
      if(dependencies==TRUE){
          installed <- rbind(installed,cbind(packages[i], pack[packages[i],"Depends"]))
          colnames(installed)<-c("Package","Dependencies")
      } else {
          installed <- rbind(installed, packages[i])
          colnames(installed)<-c("Package")
      }
      #       cat("Installed Package",packages[i])
      library(c(packages[i]), character.only=TRUE, ...)
      
    } 
  }
  list(loaded=loaded, installed=installed, error=error) 
}



#' Quickly packages and install packages that are not installed before loading
#'
#' Useful when using knitr.
#' This function allows you to check install packages then load
#' @param packages Vector of packages names to be installed
#' @param repos Repository for install.packages()
#' @keywords install.packages
#' @keywords require
#' @keywords library 
#' @export
#' @examples 
#' quickPackages(packages=c('hi','pscl','XML','quantmod','Rcpp','foreign'))

quickPackages <- function(packages, repos="http://cran.rstudio.com/",...){
  #create empty vectors to be returned as a list
  loaded <- c()
  installed <- c()
  for(i in 1:length(packages)){
    #if package is already installed just load it
    if (packages[i] %in% row.names(installed.packages())  == TRUE){
      
      #Load the Package
      library(packages[i], character.only=TRUE, ...)
      
      #List it with or without its dependencies

        loaded <- rbind(loaded,packages[i])
        colnames(loaded)<-c("Package")
      
      #if package is not already installed install it first checcking for error and then load it
    } else  if (packages[i] %in% row.names(installed.packages())  == FALSE){
      
      
      install.packages(packages[i], repos=repos)
     
        installed <- rbind(installed, packages[i])
        colnames(installed)<-c("Package")

      library(c(packages[i]), character.only=TRUE, ...)
      
    } 
  }
  list(loaded=loaded, installed=installed) 
}