I have a dataframe where I have some dulicates in the "Item" column.

[![enter image description here](https://i.stack.imgur.com/YEp2d.png)](https://i.stack.imgur.com/YEp2d.png)

I want to remove the rows where there are dulicates (adjacent) but retain the last one i.e. Get rid of the red but keep the green

[![enter image description here](https://i.stack.imgur.com/hepzy.png)](https://i.stack.imgur.com/hepzy.png)

I then want to create a new column, where apples is assumed a start, and the next row is a time delta from this.i.e.

[![enter image description here](https://i.stack.imgur.com/FtKNY.png)](https://i.stack.imgur.com/FtKNY.png)