swift switch statement cases have different and shared things to do

Question

i have code like this

switch thing {
  case thisThing:
     do thing #1
     do thing #2
  case thatThing:
     do thing #2
     do thing #3
  case anotherThing:
     do thing #4
  default:
     default
}

So, EVERY case has something that ONLY IT does. Some cases also do the same things as one or more other cases.

Is there a way to accomplish this if I don't want any repetitive code?

OR, is there a much more efficient way of doing this without switch statements at all?? I mean, I could, for example, use if statements, but like switch statements, I can't think of a way to accomplish what I want without using repetitive code.

also, this example might be more clear than the above

myFavoriteNumbers = []
myLeastFavoriteNumbers = []

switch myNumber {
case 1:
  print("my number is number 1") // do this only for case 1
  myFavoriteNumbers += [1] // do this for case 1 and case 2
case 2:
  print("this is number 2") // do this only for case 2
  myFavoriteNumbers += [2] // do this for case 1 and case 2
case 3:
  print("I don't like number 3") // do this only for case 3
  myLeastFavoriteNumbers += [3] // do this for case 3 and case 4
case 4:
  print("Number Four") // do this only for case 4
  myLeastFavoriteNumbers += [4] // do this for case 3 and case 4
default:
  print("Default")
}

Answer 1

You can use an initial separate pattern matching statement (comparable to a single case independent from the switch statement) that covers the actions that are unique for any (valid) number, and let the switch statement follow with cases that handle actions that are common for several numbers. With this you separate the unique and common logic action, where the latter is simply implemented as usual cases for any pattern matching switch implementation.

E.g., for your example

var myFavoriteNumbers: [Int] = []
var myLeastFavoriteNumbers: [Int] = []
let myNumberDescriptions = ["my number is number 1",
    "this is number 2", "I don't like number 3", "Number Four"]

let myNumber = 1

/* unique action:
    perform a unique action (given a valid number)
    and thereafter proceed to common cases */
if 1...myNumberDescriptions.count ~= myNumber {
    print(myNumberDescriptions[myNumber-1])
}

/* common cases */
switch myNumber {

/* common case: is a favourite number */
case 1...2: myFavoriteNumbers += [myNumber]

/* common case: is a least favourite number */
case 3...4: myLeastFavoriteNumbers += [myNumber]

default:
    print("Default")
}

In case the action that is unique to any number is more complex, use the same approach as above, but use more advanced logic (e.g. an event handler) for the unique action "case".