Wildcard
pattern matches and ignores the assigned value. It helps in a number of situations where we don't care about the matched values.
Consider the following example:
_ = function(param: 5)
We may use this pattern to silence the warning raised by Xcode, in cases when we don't know yet where to use the returned value.
for _ in 0...10 {
function()
}
In other cases we may not need to assing the current value in for in loop, we just want to iterate a number of times.
if let _ = optionalFunction() {
print("Function passed the optional unwrapping")
}
Finally we may more Swiftly check whether the function returns non-nil value.