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iOS Closures in Swift 2 Building Standard Library Functions Map

Posted by Wei Wei
Wei Wei
8,201 Points

There are only 3 elements in the dataStrings array.Why the console on the right shows 4 times after we call the map func

There are only 3 elements in the dataStrings array. Why the console on the right shows 4 times after we call the map function?

Dotun Ogunsakin
Dotun Ogunsakin
13,475 Points
Dotun Ogunsakin
Dotun Ogunsakin
13,475 Points

I was curious about that also, then stumbled upon the answer:

The XCode Playground appears to count the total number of operations performed in a line. So, the assignment to the variable counts as an action, and when you add the mapping loop over 3 elements, you get 4 operations on that line.

To make it clear, type the following line into a Playground page:

let a = [1, 2]; a; a; //(3 times)

The 3 operations are: the assignment, 1st variable call, 2nd variable call; all on one line in the Playgrounds page