Passing python list to a root macro as a vector without compiling

[wx2017]

I need some help on how to pass a python list to a ROOT macro as a std::vector. There are way of using boost::python but it seems the c++ code need to be compiled. I’m hoping to pass it in the following way, for example:

//// ROOT macro
void test(vector &in)
{
cout<< in.size()<<endl;
}

//… python script
import os
list = [“a”, “b”, “c”, “d”]
os.system("root -b -q ‘test(list)’ ")

The python script as is will not work. Any hint on how to do it in this style is appreciated.

[etejedor]

Hi,

There is no automatic conversion from Python list to std::vector. So from Python, you can do:

import ROOT
from ROOT import gROOT
gROOT.LoadMacro("test.C+")
v = ROOT.std.vector('char')()
for c in ['a', 'b', 'c', 'd']:
    v.push_back(c)
ROOT.test(v)

[wx2017]

That works great. Thanks!