# intersection(with:) Returns the intersection between the receiver and the specified date interval. ``` func intersection(with dateInterval: DateInterval) -> DateInterval? ``` ## Parameters `dateInterval` The date interval with which to calculate the intersection of the receiver. ## Return Value A date interval for the intersection of the receiver and `dateInterval`, or `nil` if no intersection occurs. ## Discussion Calculating the intersection of date intervals is a commutative and associative operation. The intersection of a date interval with itself is equal to itself. The following figure illustrates five `NSDateInterval` objects plotted on an arbitrary time axis. Each date interval spans its [`duration`](/documentation/Foundation/NSDateInterval/duration) from left to right, from its [`startDate`](/documentation/Foundation/NSDateInterval/startDate) to its [`endDate`](/documentation/Foundation/NSDateInterval/endDate).  The date intervals labeled **A** and **B** do not intersect, because the [`startDate`](/documentation/Foundation/NSDateInterval/startDate) of **B** occurs later than the [`endDate`](/documentation/Foundation/NSDateInterval/endDate) of **A**. The date intervals labeled **C** and **D** do intersect. The date interval labeled **E** represents the result of calculating the intersection between **C** and **D**. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)