Use logical operator as combine closure in reduce

Question

I am trying to reduce an array of Bools by applying the logical operator OR (||) using the following code, however I get an error:

func reduceBools(values: [Bool]) -> Bool {     return values.reduce(false, combine: ||) } 

Ambiguous reference to member '||'

Analogously for integers the code works like a charm.

func reduceInts(values: [Int]) -> Int {     return values.reduce(0, combine: +) } 

I was able to make it work by adding a || function (code below) or using a { $0 || $1 } closure but I dislike these approaches and I would prefer simply passing the operator.

func ||(lhs: Bool, rhs: Bool) -> Bool {     return lhs || rhs } 

The same thing happens for the logical AND (&&) operator.

How can I make it work without using the hack above?

Answer 1

As an alternative, you could use the following approach

// || func reduceBoolsOr(values: [Bool]) -> Bool {     return values.contains(true) }  // && func reduceBoolsAnd(values: [Bool]) -> Bool {     return !values.contains(false) } 

Note that .reduce comes with an overhead. If the end result is the importance of your question (rather than enquiring above the unexpected behaviour of || and && operators in this context), then perhaps the pragmatic approach above can be of help, even if it doesn't really reduce the array, however producing the same result due to the simple nature of the boolean type.

Answer 2

Swift 4.2+ / Xcode 10.0+

In modern versions of Swift there is allSatisfy function, which checks all elements for satisfying some rule.

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In OP's case:

values.allSatisfy { $0 }