How to modify TTree entry?

ROOT
1

Please, explain the next question.

I’d like to load TTree, modify some entries (with predefined entry index)and save again.
I’s not clear for me how to modify entry.

Thanks!

2

Hi,

TTree are designed as a write-once, read-many type of persistent container. It is practically impossible to modify existing entry.

You can other either make a modify copy of your TTree (see $ROOTSYS/tutorials/copytree*.C) or create a new TTree with just the modified value and use it as ‘friend’ of the original tree.

Cheers,
Philippe.