Inserting entries into a tree

ROOT
1

Hi all,

Is there an easy way to insert entries into a tree, i.e. not appending them to the end of the tree like with TTree::Fill but to insert them on a specified position?

Thx, Mathias

2

What do you mean by “on a specified position”?
May be you can have a look at the copytree tutorials.

Rene

3

When comparing a Tree with a STL vector TTree::Fill corresponds to vector::push_back, i.e. an element is inserted at the very end of the tree/vector. What I am looking for is something like the vector::insert method That inserts an entry into a tree but not necessarily at its end. One way to do that would be copying a tree up to a certain point, inserting the new value and continuing the copy-operation. I was just wondering if there is no way to do an in-place insertion, i.e. inserting an entry into an existing tree without having to copy it.

Cheers, Mathias

4

This would be an expensive operation.
If you look at tutorial copytree3.C, you can easily achieve this.
Modify the loop to
-copy entries 0 to N
-fill the destination Tree with your new entry
-continue the loop

Rene

5

Ok, thats exactly what I did.

Thanks Rene,

Mathias

6

[quote=“Mathias”]When comparing a Tree with a STL vector TTree::Fill corresponds to vector::push_back, i.e. an element is inserted at the very end of the tree/vector. What I am looking for is something like the vector::insert method That inserts an entry into a tree but not necessarily at its end. One way to do that would be copying a tree up to a certain point, inserting the new value and continuing the copy-operation. I was just wondering if there is no way to do an in-place insertion, i.e. inserting an entry into an existing tree without having to copy it.
[/quote]

Just out of curiosity, why not just “push” the entries on the end? (I could almost imagine doing what you want to create a tree for debugging purposes…)

Cheers,
Charles

7

It’s just to maintain the order in time for my events. I want to insert some artificial events to get rid of some deadtime purposes of my experiment. Therefore I have to insert these events into specific positions to maintain the chronicle order of my events. That’s it.