prefix(_:)
Returns an asynchronous sequence, up to the specified maximum length, containing the initial elements of the base asynchronous sequence.
- iOS
- 13.0+
- macOS
- 10.15+
- tvOS
- 13.0+
- watchOS
- 6.0+
func prefix(_ count: Int) -> AsyncPrefixSequence<Self> Parameters
- count
The maximum number of elements to return. The value of
countmust be greater than or equal to zero.
Returns
An asynchronous sequence starting at the beginning of the base sequence with at most count elements.
Use prefix(_:) to reduce the number of elements produced by the asynchronous sequence.
In this example, an asynchronous sequence called Counter produces Int values from 1 to 10. The prefix(_:) method causes the modified sequence to pass through the first six values, then end.
for await number in Counter(howHigh: 10).prefix(6) {
print(number, terminator: " ")
}
// Prints "1 2 3 4 5 6 "If the count passed to prefix(_:) exceeds the number of elements in the base sequence, the result contains all of the elements in the sequence.