--- 1 ---
val myScoreList = listOf(12,60,0,38)
val sum = 0
for(score: Int in myScoreList){
  sum += score //same as sum = sum+score
}
Log.i("",sum.toString()) //returns 100

--- 2 ---
val name = "Doge"
for(character: Char in name){
  Log.i("",character.toString())
} //logs "D","o","g","e"

--- 3 ---
val myEmailList = arrayListOf("john.doe@dogemail.com",
                               "muhammad.li@dogemail.com",
                               "xoxoILoVeKoTLiNxoxo@notdogemail.com",
                               "totallyNotScammer@doggiemail.com",
                               "eehoohoohoohahh@dogemail.com")
val myDogemailList = arrayListOf<String>()
for(email: String in myEmailList){
  val atSignIndex = email.indexOf("@")
  if(email.substring(atSignIndex+1) == "dogemail.com"){ //substring from after the "@" sign, to the end of the string
    myDogemailList.add(email)
  }
} //now myDogemailList = ["john.doe@dogemail.com", "muhammad.li@dogemail.com", "eehoohoohoohahh@dogemail.com"]

--- 4 ---
val myPictureBitmap: ArrayList<ArrayList<ArrayList<Int>>> = arrayListOf(
  arrayListOf( arrayListOf(255,0,0), arrayListOf(255,127,0), arrayListOf(255,255,0) ), //row 0
  arrayListOf( arrayListOf(0,255,0), arrayListOf(0,255,255), arrayListOf(0,0,255) ), //row 1
  arrayListOf( arrayListOf(127,0,255), arrayListOf(255,255,255), arrayListOf(0,0,0) ) //row 2
)              //column 0              //column 1                //column 2
for(row: ArrayList<ArrayList<Int>> in myPictureBitmap){ //for each row of the picture
  for(pixel: ArrayList<Int> in row){ //for each column (pixel) in the row
    pixel[0] = 255-pixel[0]
    pixel[1] = 255-pixel[1]
    pixel[2] = 255-pixel[2] //color inversion
  }
}

/*from   [ [ [255,0,0],[255,127,0],[255,255,0] ],
           [ [0,255,0],[0,255,255],[0,0,255]   ],
           [ [127,0,255],[255,255,255],[0,0,0] ] ]

turns to [ [ [0,255,255],[0,128,255],[0,0,255] ],
           [ [255,0,255],[255,0,0],[255,255,0] ],
           [ [128,255,0],[0,0,0],[255,255,255] ] ]
*/