formIndex(_:offsetBy:limitedBy:)
Offsets the given index by the specified distance, or so that it equals the given limiting index.
Available because
Self
conforms toCollection
.
func formIndex(_ i: inout Self.Index, offsetBy distance: Int, limitedBy limit: Self.Index) -> Bool
Parameters
- i
A valid index of the collection.
- distance
The distance to offset
i
.distance
must not be negative unless the collection conforms to theBidirectionalCollection
protocol.- limit
A valid index of the collection to use as a limit. If
distance > 0
, a limit that is less thani
has no effect. Likewise, ifdistance < 0
, a limit that is greater thani
has no effect.
Returns
true
if i
has been offset by exactly distance
steps without going beyond limit
; otherwise, false
. When the return value is false
, the value of i
is equal to limit
.
Overview
The value passed as distance
must not offset i
beyond the bounds of the collection, unless the index passed as limit
prevents offsetting beyond those bounds.