# Load packages needed;
library(XML)
library(googleVis)</p>

<h1 id="set-cran-depository">set CRAN depository;</h1>
<p>CRAN.mirr <- “http://cran.r-project.org/”
CRAN.home <- “web/packages/available_packages_by_name.html”</p>

<h1 id="read-in-packages-name-and-description">read in packages name and description;</h1>
<p>pkg <- readHTMLTable(paste(CRAN.mirr, CRAN.home, sep = “”), skip = 1,)[[1]]
names(pkg) <- c(“Name”, “Description”)
pkg <- pkg[!is.na(pkg$Name),]
pkg[,1] <- as.character(pkg[,1])
pkg[,2] <- as.character(pkg[,2])</p>

<h1 id="define-a-function-to-convert-date-format-11-jun-2011-to-2011-06-11">Define a function to convert date format “11-Jun-2011” to “2011-06-11”;</h1>
<p>as.posix <- function(x) {
  day <- substr(x, 1, 2)
  mth <- substr(x, 4, 6)
  yr  <- substr(x, 8, 11)
  Mth <- c(“Jan”, “Feb”, “Mar”, “Apr”, “May”, “Jun”, “Jul”, “Aug”, “Sep”, “Oct”, “Nov”, “Dec”)
  mth <- unlist(sapply(mth, FUN = function(x) {
    m <- which(Mth == x)
    if (nchar(m) == 1) m <- paste(“0”, m, sep = “”)
    return(m)}))
  paste(yr, mth, day, sep = “-“)
}</p>

<h1 id="create-a-list-to-contain-detail-information-of-each-package">Create a list to contain detail information of each package;</h1>
<p># This process will take about 15 minutes;
PKG <- list()
pb <- txtProgressBar(min = 0, max = nrow(pkg), style = 3)
for (i in 1:nrow(pkg)) {
  pkg.nam <- pkg$Name[i]
  pkg.url <- paste(CRAN.mirr, “web/packages/”, pkg.nam, “/index.html”, sep = “”)
  pkg.des <- readHTMLTable(pkg.url)
  names(pkg.des) <- c(“Description”, “Downloads”, “Dependency”)[1:length(pkg.des)]
  if (“Old sources:” %in% pkg.des$Downloads$V1) {
    hist.url <- paste(CRAN.mirr, “src/contrib/Archive/”, pkg.nam, sep = “”)
    hist.dat <- readHTMLTable(hist.url, skip = 2)[[1]][, 2:3]
    names(hist.dat) <- c(“Name”, “Date”)
    hist.dat <- hist.dat[!is.na(hist.dat$Name),]
    hist.dat$Date <- as.posix(hist.dat$Date)
    pkg.des[[“History”]] <- hist.dat
  }
  for (l in 1:length(pkg.des)) {
    pkg.des[[l]][,1] <- as.character(pkg.des[[l]][,1])
    pkg.des[[l]][,2] <- as.character(pkg.des[[l]][,2])
  }
  PKG[[pkg.nam]] <- pkg.des
  setTxtProgressBar(pb, i)
}
close(pb)</p>

<h1 id="extract-the-date-of-the-first-version-of-each-package">Extract the date of the first version of each package;</h1>
<p>pkg.trend <- data.frame(pkg.name = names(PKG))
for (i in 1:nrow(pkg.trend)) {
  pkg <- pkg.trend$pkg.name[i]
  pkg.des <- PKG[[pkg]]
  if (“History” %in% names(pkg.des)) {
    pkg.trend$Date.1[i] <- as.character(min(pkg.des$History$Date))
  }else {
    pkg.trend$Date.1[i] <-
    pkg.des$Description$V2[which(pkg.des$Description$V1 == “Published:”)]
  }
}</p>

<h1 id="aggregates-the-package-number-for-each-month">aggregates the package number for each month;</h1>
<p>pkg.trend$Date.2 <- paste(substr(pkg.trend$Date.1, 1, 7), “01”, sep = “-“)
pkg.trend$Date.2 <- as.POSIXct(pkg.trend$Date.2, format = “%Y-%m-%d”)
pkg.dat <- with(pkg.trend, aggregate(list(Num = Date.2), list(Date = Date.2), length))
pkg.dat$Num1 <- cumsum(pkg.dat$Num)</p>

<h1 id="display-growth-curve-using-googlevis">Display growth curve using GoogleVis;</h1>
<p>Line1 <- gvisLineChart(pkg.dat, xvar=”Date”, yvar=”Num1”)
Line2 <- gvisLineChart(pkg.dat, xvar=”Date”, yvar=”Num”)
plot(Line1)
plot(Line2)</p>

<p>