I have been trying to learn the names of the Swift features recently so that I can communicate with people with these names.
For example
!
is added to the end of a type name, it's called an "implicitly unwrapped optional type"guard
denotes a "guard statement"if let x = someOptional
is called "Optional binding"case 0...9:
is an example of "pattern matching" in switch statementsBut there is one feature that I don't know the name of.
Usually, I write this kind of code because C-style for loops are deprecated:
for _ in 0...9 { print("hello") //print hello 10 times }
I want to know what the underscore is called.
I know that this is from Ruby. So I think it will have the same name as the underscore in Ruby. So what exactly is the underscore called?
My guesses:
Is there an official term for this? If there isn't, how would I call this in a casual conversation about my code?
It's called a wildcard pattern:
Wildcard Pattern
A wildcard pattern matches and ignores any value and consists of an underscore (
_
). Use a wildcard pattern when you don’t care about the values being matched against. For example, the following code iterates through the closed range1...3
, ignoring the current value of the range on each iteration of the loop:for _ in 1...3 { // Do something three times. }
https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Patterns.html#//apple_ref/doc/uid/TP40014097-CH36-ID420
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