[numarray] mean vector of 2d matrix

[beliavsky at aol.com]

Curzio Basso <curzio.basso at unibas.ch> wrote in message news:<409f9edd$1 at maser.urz.unibas.ch>...
> Hi all,
> 
> I was wondering what is the best way to compute the mean vector of a 
> matrix. Currently I'm doing this:

With Numeric, one can use the 'average' function to compute the average along
an axis, or the average of all elements when the axis argument is set to None.
See p317 of Martelli's "Python in a Nutshell" book. For example, the code 

from Numeric import zeros,Float,average
nr = 3
nc = 2
xx = zeros([nr,nc],Float)
for i in range(nr):
    for j in range(nc):
        xx[i,j] = i + 10.0*j
print xx
for i in [None,0,1]: print "\n",i,average(xx,axis=i)

produces output

[[  0.  10.]
 [  1.  11.]
 [  2.  12.]]

None 6.0

0 [  1.  11.]

1 [ 5.  6.  7.]