How to create and use a branch with a C char array from PyROOT

[etejedor]

Hi,

You can use a character array in Python, with the array.array type. Here you can find an explanation:

Branching array of char in ttree

Gabriel, not exactly: CINT saves you by allocating a larger buffer for the string variable that you allocate, and probably initializes it to \0, or what you did in the C++ macro would not have worked (try compiling it, and see it crash at runtime in several places: the assignments beyond the empty string bounds as well as in the print/scan). In python, you get exactly what you asked for: a character array. That is not a string. You can get the same behavior by creating a larger buffer, and th…

So something like:
s=array('c', 'ab\0')

which you can pass to tr.Branch and you can modify before each fill with the value you want for the next tree entry.