Filter an array based on empty value in Swift

Question

I am trying to filter an array of dictionaries. The below code is the sample of the scenario i am looking for

let names = [ 
    [ "firstName":"Chris","middleName":"Alex"],
    ["firstName":"Matt","middleName":""],
    ["firstName":"John","middleName":"Luke"],
    ["firstName":"Mary","middleName":"John"],
]

The final result should be an array for whom there is a middle name.

Answer 1

This did the trick

names.filter {
  if let middleName = $0["middleName"] {
    return !middleName.isEmpty
  }
  return false
}

Answer 2

Slightly shorter:

let result = names.filter { $0["middleName"]?.isEmpty == false }

This handles all three possible cases:

• If the middle name exists and is not an empty string, then $0["middleName"]?.isEmpty evaluates to false and the predicate returns true.
• If the middle name exists and is empty string, then $0["middleName"]?.isEmpty evaluates to true and the predicate returns false.
• If the middle name does not exist, then $0["middleName"]?.isEmpty evaluates to nil and the predicate returns false (because nil != false).