[R] newbie: grading an histogram for several classes of the same discipline

Mauricio Ortiz Calvao orca at if.ufrj.br
Tue Oct 27 21:17:51 CET 2009

Hi there

Sorry for the simple question, but I have been unable to find an answer.

I am the coordinator of a basic discipline in a university; we have 
several classes taking this discipline and I would like to compare the 
grades, via a histogram for the distinct classes.

Concretely, I have five ascii files (named according to each class: EC, 
EE, EM, EP, EQ) with three columns each, named according to the exams 
(P1, P2 and PF: first, second and final). Each one of the files has a 
different number of columns, owing to the DIFFERENT number of students 
in each class; example:


P1  P2  PF
3.4 4.0 5.9
4.3 7.0 2.0
7.8 5.8 7.0


P1  P2  PF
6.3 5.0 7.4
4.9 4.9 8.5
7.7 2.5 5.3
4.6 7.8 5.7
7.7 7.0 5.6
2.4 3.8 5.4



I would like to create a certain R data type/object/class such that it 
kind of stores all five (5) files into it [dataframe??]; then I would 
give a command that would create five histograms in five distinct 
subplots of the same figure, so that we could visually compare the 
performance of the different classes in each exam...

Thanks for any guidance!

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