var array = ["1","2","3"]
print(array[0])
//1
array.remove(at: 0)
print(array[0])
//2

var dict = [
"1":"One",
"2":"Two",
"3":"Three"
 ]

if let value = dict["1"]{
   print(value)
   //One
}

if let index = dict.index(forKey:"1"){
   dict.remove(at: index)
   print(dict)
   //["2":"Two","3":"Three"]
}