filter(_:)
Creates an asynchronous sequence that contains, in order, the elements of the base sequence that satisfy the given predicate.
Declaration
@preconcurrency func filter(_ isIncluded: @escaping @Sendable (Self.Element) async -> Bool) -> AsyncFilterSequence<Self>Parameters
- isIncluded:
A closure that takes an element of the asynchronous sequence as its argument and returns a Boolean value that indicates whether to include the element in the filtered sequence.
Return Value
An asynchronous sequence that contains, in order, the elements of the base sequence that satisfy the given predicate.
Discussion
In this example, an asynchronous sequence called Counter produces Int values from 1 to 10. The filter(_:) method returns true for even values and false for odd values, thereby filtering out the odd values:
let stream = Counter(howHigh: 10)
.filter { $0 % 2 == 0 }
for await number in stream {
print(number, terminator: " ")
}
// Prints "2 4 6 8 10 "