genfromtxt and comment identifier

simona bellavista afylot at
Fri Apr 15 12:58:47 EDT 2011

Hi All,

I have a problem with reading data from a file using genfromtxt of
numpy module.

I have prepared a minimal example similar to the ones presented in

The script is

import numpy as np
from StringIO import StringIO
file = open('esempio.dat')
for line in file.xreadlines() :
    if not line : break
    print line
    np.genfromtxt(StringIO(line), comments="#", delimiter=",")

I have a data file - esempio.dat - like the following:

# Skip me !
# Skip me too !
1, 2
3, 4
5, 6 #This is the third line of the data
7, 8
# And here comes the last line
9, 0

The code is breaking at the first line, it looks like it doesn't
recognize # like comment identifier.

The error in the python interpreter is

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "", line 7, in <module>
    np.genfromtxt(StringIO(line), comments="#", delimiter=",")
  File "/opt/numpy/1.5.1/lib/python2.6/site-packages/numpy/lib/", line 1174, in genfromtxt
    raise IOError('End-of-file reached before encountering data.')
IOError: End-of-file reached before encountering data.

It is clear that I haven't understood something, what am I doing


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