Some numpy notes

here are some numpy notes..
#create a numpy array

a = array([1,2,4])

#make this a column vector
a = a.reshape(len(a),1)

#append a new column vector to it
a = concatenate((a,a),axis=1)

#the append function is not working for me..so i will stick to concatenate

now let me give  a simple program to read a file of real numbers, compute the average of each row and write a new file with this columns of averages appended..
You need the scitools package and numpy installed to execute this

#program to read a file containing real numbers and sum the rows and take average. add the average as a new column and save
import sys
from numpy import *

try:
    infile = sys.argv[1]
    outfile = sys.argv[2]
except:
    print "lafda aiti tamma"

import scitools.filetable as ft
#x = []
#y = []
fin = open(infile, 'r')
fout = open(outfile, 'w')

#now read the x,y pairs from command line
#if len(sys.argv) % 2 != 0:
#    print "must enter even no of digits"
#    exit

#for i in range(2,len(sys.argv[2:])): #leave out the first two elements of sys.argv ie program name and output file
#    y.append(float(sys.argv[i])) if (i%2) else x.append(float(sys.argv[i]))

#x = array(x)
#y = array(y)

#read the table from the file and store as a matrix
table = ft.read(fin)

num_rows = table.shape[0]
num_columns = table.shape[1]
avg_col = []


for i in range(num_rows):
    avg_col.append(mean(table[i]))
      

avg_col = array(avg_col)
print table.shape
print avg_col.shape
avg_col = avg_col.reshape(len(avg_col),1)
table = concatenate((table,avg_col),axis=1)
ft.write(fout,table)