How can I get key s value from dictionary in Swift

Question

I have a Swift dictionary  I want to get my key s value  Object for key method is not working for me  How do you get the value for a dictionary s key   This is my dictionary   var companies     AAPL     Apple Inc    GOOG     Google Inc    AMZN     Amazon com  Inc    FB     Facebook Inc    for name in companies keys        print companies objectForKey  AAPL

User · Answer

From Apple Docs

You can use subscript syntax to retrieve a value from the dictionary for a particular key. Because it is possible to request a key for which no value exists, a dictionary’s subscript returns an optional value of the dictionary’s value type. If the dictionary contains a value for the requested key, the subscript returns an optional value containing the existing value for that key. Otherwise, the subscript returns nil:

https://developer.apple.com/documentation/swift/dictionary

if let airportName = airports["DUB"] {
    print("The name of the airport is \(airportName).")
} else {
    print("That airport is not in the airports dictionary.")
}
// prints "The name of the airport is Dublin Airport."

User · Answer

Use subscripting to access the value for a dictionary key  This will return an Optional   let apple  String    companies  AAPL     or  if let apple   companies  AAPL                      You can also enumerate over all of the keys and values   var companies     AAPL     Apple Inc    GOOG     Google Inc    AMZN     Amazon com  Inc    FB     Facebook Inc    for  key  value  in companies       print    key  - gt    value        Or enumerate over all of the values   for value in Array companies values        print    value

User · Answer

For finding value use below if let a   companies  quot AAPL quot           a is the value    For traversing through the dictionary for  key  value  in companies       print key  quot --- quot   value     Finally for searching key by value you firstly add the extension extension Dictionary where Value  Equatable       func findKey forValue val  Value  - gt  Key            return first where     1    val     key          Then just call companies findKey val    quot Apple Inc quot

[dictionary] How can I get key's value from dictionary in Swift?

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