Double question mark is a nil-coalescing operator . In plain terms, it is just a shorthand for saying != nil . First it checks if the the return value is nil, if it is indeed nil, then the left value is presented, and if it is nil then the right value is presented.
Read moreWhat is use of === in Swift?
The === or identity operator compares the identity of the objects . It checks whether the operands refer to the same object. As you can see, arr1 and arr2 do not refer to the same object, despite the objects being equal.
Read moreWhat does == and === mean?
== is used for comparison between two variables irrespective of the datatype of variable. === is used for comparision between two variables but this will check strict type, which means it will check datatype and compare two values.
Read moreWhat does += mean in Swift?
The expression a += 2 is shorthand for a = a + 2 . Effectively, the addition and the assignment are combined into one operator that performs both tasks at the same time . Note. The compound assignment operators don’t return a value. For example, you can’t write let b = a += 2 .
Read moreWhat is _ mean in Swift?
The _ is not necessary for function calls. It is just used to indicate that something does not need to have a name . In regards to how you would refer to your function, You would not have to pass any name for the function call.
Read moreHow do I use the SF symbol?
How to use SF Symbols in Swift
Read moreWhat is == and === in Swift?
== is used to check if two variables are equal i.e 2 == 2 . But in case of === it stands for equality i.e if two instances referring to the same object example in case of classes a reference is created which is held by many other instances. Follow this answer to receive notifications.2 Haz 2014
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