// connecting to url

// sending data

//wr.write("Fdate=2001-9-18&Tdate=2012-09-25")

// receiving data as page made of HTML

// received data can be seen with

// println(page)

// regular expression for extracting rows: 

// - the usual . would exclude newlines, 

// - therefore we have to use [\S\s], which really 

//   matches everything

// - *? is the "lazy" version of *

val regex1 = """<tr align="center">[\S\s]*?</tr>""".r

// data in rows

// println(rows)

// extracting row entries (date, PM_10, SO_2, NO_2)

// the use of (..) allows us to extract the matched text

val regex2 = """<td align="center">([\S\s]*?)</td>""".r

def extract(s: String) : List[String] = {

  for (regex2(value) <- regex2.findAllIn(s).toList) yield value.trim

val data = rows.map(extract)

def compare(i: Int)(e: List[String], f: List[String]) = e(i).toInt > f(i).toInt

println("The day with the highest particle pollution (PM_10)")

println(data.sortWith(compare(1)).head.mkString(","))

println("The day with the highest sulfur dioxide (SO_2)")

println(data.sortWith(compare(2)).head.mkString(","))

println("The day with the highest nitro dioxide (NO_2)")

println(data.sortWith(compare(3)).head.mkString(","))

println("The day(s) with the highest PM_10")

println("The day(s) with the highest SO_2")

println("The day(s) with the highest NO_2")