The root primer page

The ROOT Primer Page

A Beginners Guide to the ROOT Data Analysis System

Last Update Mon Jul 27 09:17:08 CEST 1998

ROOT has the following characteristics:

The ROOT mailing list: roottalk

(Instructions taken from an email of, 15/01/96)

Quick start for PAW users:

PAW2ROOT syntax conversion table
An updated version by David d'Enterria is here

The Primer

Part A: General Remarks
Part B: List of objects
Canvas | Fit | Function | Graph | Histogram | Ntuple | Postscript
Part C:Adding own classes to root (to be added soon)

Part A:General Remarks

Part B:List of ROOT Objects


Graphical object.



Mathematical object.


x-y plot with or without error bars


A histogram is a data structure containing 1D, 2D or 3D channels. The number of events is stored as a function of the channel index.


A NTuple is a matrice-like data structure with n rows (corresponding e.g. to the number of events) and m columns (corresponding e.g. to the number of parameters per event).

For example you may have a data file (ASCII) like xyz.dat and you want to (a) read it and (b) put it into a NTuple Structure. Do it like this:


Graphical output into a printable file.

Part C:Adding own classes to root

Remark: Although we think that root is a brilliant concept, this page claims to be independent from the root development team. Thus, hopefully objectivity is achieved.

Update Information:

97/01/17 Page released at Technical University Dresden
97/02/12 Page added to "Applications using root" on
97/07/03 Page moved to Tokyo Metropolitan University
97/07/03 Page moved to CERN

Questions/Comments | Sören Lange, 97/07/03