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# deltaY

The y-coordinate change for scroll wheel, mouse-move, mouse-drag, and swipe events.

```
var deltaY: CGFloat { get }
```

## Discussion

This property is only valid for scroll wheel, mouse-move, mouse-drag, and swipe events. For swipe events, a nonzero value represents a horizontal swipe; `-1.0` corresponds to swipe down and `1.0` corresponds to swipe up.

For scroll wheel events, use [`scrollingDeltaY`](/documentation/AppKit/NSEvent/scrollingDeltaY) instead.

---

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