When to use "" , () , ("") , [] , [""]

• "" -The quotation marks you use for Strings
• [] -The braces you use for an Array or Dictionaries
• () - The parentheses you use for putting parameters of functions

So if you got quotation marks inside a brace like:

var arrayForDemo: Array = ["This", "is","array","of","strings"] 

You have an Array of strings.

The ("") is used for taking strings parameters for your function

func fullName(firstName: String, lastName: String) -> String {
    return "\(firstName) \(lastName)"
}
fullName("Bob", "Tuesday")

As you can see, the code create a function that take two strings as parameters, when the function is called you use the (""), because you are calling strings.

Obs: The () empty is used when the function take no parameters.

Hope that helps, any further questions fell free to contact me! I highly recommend you read A Swift Tour on Swift Documentation.

This is what I've seen consistently in Swift so far...

• Strings (usually text) go in " "
• Arrays (an unordered list of elements... can be strings, numbers etc) go in [ ]
• String in an array would be ["example1", "example 2"]
• Parameters and everything else (usually for a function) go in ( )
• If passing a string to as a parameter it would look like (" ")