Filling histogram bug

I’m trying to fill a histogram with data from a tree, which has 40 bins and x values from -200 to 200. The bin content at x=10 is the last bin content added to the content which is supposed to be at that bin. The way I am filling the histogram is as follows(t is the tree with branches zPosition and efficiency and hist is the histogram).

for x in xrange(40):
t.Show(x)
hist.fill(t.zPosition, t.efficiency)

Is there something wrong with how I’m filling the histogram, or a more proper way to do it?

-B

Hi,

supposing that “t” is your tree, and you want to fill your histogram with the zPosition values weighted according to the efficiency, this would be the right syntax:

for event in t:
hist.fill(event.zPosition, event.efficiency)

Danilo