A TTree.Project like method to fill many histograms simultan

[fnuti]

Hi all,
I find the method Project of the TTree class very easy and very useful to make a histogram with whatever complex selection. Its potential however is reduced because for each histogram you want to make it has to loop again all over the tree. If I want to produce 100 histograms with the same selection, the program now will loop 100 times to fill all the histograms but technically it would be possible to fill them in just one loop. So my question is: is there another method of TTree class that allows to fill simultaneously more histograms or is it possible that in the future the Project method will be modified to fill more histograms in one loop for instance by accepting as parameter a vector of histograms?
Thanks
Francesco

[Wile_E_Coyote]

Export leaf histogram to ascii

https://root-forum.cern.ch/t/header-files-for-trees/16308/2

CloneTree in TSelector (or CopyTree)

Hi Julien, The skeleton created by MakeSelector puts the TTree in mode where the reading of the TTree content is decomposed in ints and floats (‘MakeClass’ mode). This mode is currently incompatible with cloning the TTree (mismatch in what the writing and reading code expect). The result of MakeProxy on the other hand is compatible with CloneTree and should be such that the change in your code should be minimal. Cheers, Philippe.