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--- root:pyroot_th1 [2017/06/22 17:50] – [Handling TH1 histograms] iwn
+++ root:pyroot_th1 [2017/09/05 10:34] – [Handling TH1 histograms] iwn
@@ Line 1: / Line 1: @@
+[[root:root|Getting started with ROOT]] -> [[root:pyroot|Useful pyROOT snippets]] → [[root:pyroot_th1|Handling TH1 histograms]]
 ====== Handling TH1 histograms ======
-===== Import ROOT classes =====
+[[https://root.cern.ch/doc/master/classTH1.html|Here]] is the class manual for ''TH1''.
+===== Importing ROOT classes =====
-To use ''TH1D'' in ''python'', you can either do
+To use ''TH1D'' in ''python'', you can either only import a ''TH1D'' class:
 <code python>
 from ROOT import TH1D
 hist = TH1D("hist_name","hist_title",100,0,100)
 </code>
-or
+or //all// classes:
 <code python>
 from ROOT import * # loads all classes, and thus takes longer
 hist = TH1D("hist_name","hist_title",100,0,100)
 </code>
-or
+or only the ''ROOT'' module:
 <code python>
 import ROOT
@@ Line 56: / Line 61: @@
 tree.Draw("abs(eta) >> hist_name")
 tree.Draw("pt1*(eta1<2.4) + pt2*(eta2<2.4) >> hist_name") # boolean expressions
+</code>
+This also includes custom functions, which you can load into ''ROOT'' with a ''C'' file:
+<code python>
+from ROOT import gROOT, ...
+gROOT.Macro("myfunctions.C+")
+...
+tree.Draw("deltaR(eta1,phi1,eta2,phi2) >> hist_name")    # deltaR     function defined in "myfunctions.C+"
+tree.Draw("pt1 >> hist_name","(pt>30)*weightEta1(eta1)") # weightEta1 function defined in "myfunctions.C+"
 </code>

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