Import 2 columns from 8 .csv files into pandas df (side by side) and write a new csv

I have 8 .csv files with 16 columns and "n" rows with no Header. I want to parse each of these .csv and get column [0, 8] [#where column 0 is the value of x, y, z etc and column 8 is always the value of a#] and put the data into a new.csv. Once this is done, the new.csv should have 16 columns (2 from each input.csv) and "n" rows.

Now, I want to just take the average of Column[1,3,5,7,9,11,13,15] from new.csv and append it to another file or this file. Basically in the new csv, i want to have the average of colum[8] form the input files and each of the column[0] from the input files. So the final output expecting should have a shape of 9 columns and n rows.
sample input files:

    a.csv:
    5.42E+05    6.52E+05    2.17E+04    2.73E+04    2.58E+04    2.33E+04    2.81E+04    3.37E+04    1.08E+08    1.10E+08    2.54E+05    3.21E+05    2.99E+05    2.74E+05    3.39E+05    4.07E+05
    4.64E+04    1.15E+06    1.96E+04    2.53E+04    2.39E+04    2.37E+04    1.98E+04    2.85E+04    6.18E+05    2.17E+08    2.30E+05    3.02E+05    2.75E+05    2.77E+05    2.33E+05    3.42E+05
    4.36E+04    1.13E+06    5.72E+04    2.71E+04    2.77E+04    2.37E+04    2.62E+04    7.35E+04    5.78E+05    2.17E+08    9.26E+05    3.25E+05    3.20E+05    2.72E+05    3.20E+05    1.46E+06
    4.32E+04    1.02E+06    1.47E+05    2.63E+04    3.05E+04    2.26E+04    2.89E+04    2.45E+04    5.70E+05    2.15E+08    2.78E+06    3.02E+05    3.58E+05    2.63E+05    3.49E+05    2.87E+05
    4.44E+04    7.83E+05    1.58E+05    2.95E+04    2.71E+05    2.71E+04    3.67E+04    2.85E+04    5.86E+05    1.61E+08    2.89E+06    3.48E+05    5.39E+07    3.14E+05    4.49E+05    3.39E+05
    1.47E+05    1.02E+06    2.09E+04    2.72E+04    2.66E+04    6.18E+04    3.50E+04    3.00E+04    2.72E+06    2.15E+08    2.46E+05    3.18E+05    3.07E+05    9.91E+05    7.18E+05    3.71E+05
    1.81E+05    7.67E+05    1.94E+04    5.05E+04    2.62E+04    4.50E+04    2.92E+04    2.86E+04    3.16E+06    1.61E+08    2.28E+05    4.84E+06    3.10E+05    5.31E+06    3.49E+05    3.58E+05
    4.94E+05    1.34E+05    6.99E+04    8.76E+05    5.51E+04    5.27E+04    3.34E+05    1.30E+05    1.35E+07    3.59E+06    1.66E+06    1.64E+08    1.03E+06    1.12E+06    5.56E+07    3.37E+06
    4.79E+04    1.38E+05    2.66E+04    1.02E+06    2.85E+04    2.88E+04    2.89E+04    3.26E+04    6.12E+05    2.72E+06    3.21E+05    2.15E+08    3.29E+05    3.39E+05    3.40E+05    4.04E+05
    4.51E+04    6.44E+05    3.02E+04    5.24E+05    2.72E+04    1.89E+04    2.42E+04    3.21E+04    5.97E+05    1.10E+08    3.65E+05    1.07E+08    3.17E+05    2.17E+05    2.85E+05    3.80E+05

 
    b.csv:
        4.25E+03    1.83E+03    1.09E+03    1.35E+03    1.18E+03    1.24E+03    1.16E+03    1.28E+03    1.08E+08    1.10E+08    2.51E+05    3.13E+05    2.80E+05    2.64E+05    3.23E+05    3.32E+05
        4.47E+03    2.20E+03    1.16E+03    1.46E+03    1.28E+03    1.21E+03    1.17E+03    1.36E+03    6.01E+05    2.17E+08    2.92E+05    3.59E+05    3.34E+05    2.84E+05    3.14E+05    3.86E+05
        5.12E+03    1.85E+03    1.62E+03    1.59E+03    1.93E+03    1.36E+03    1.36E+03    1.42E+03    7.19E+05    2.16E+08    1.60E+06    7.14E+06    7.10E+05    8.74E+05    8.67E+05    1.37E+06
        4.32E+03    1.53E+03    2.03E+03    1.11E+03    1.18E+03    1.18E+03    1.52E+03    1.18E+03    5.81E+05    2.15E+08    2.70E+06    2.84E+05    3.24E+05    3.12E+05    4.25E+05    3.65E+05
        4.64E+03    1.53E+03    2.07E+03    1.15E+03    1.15E+03    1.25E+03    1.50E+03    1.13E+03    1.17E+06    1.61E+08    2.74E+06    2.98E+05    2.82E+05    5.38E+07    4.16E+05    3.41E+05
        5.03E+03    1.61E+03    1.17E+03    1.15E+03    1.02E+03    1.12E+03    1.40E+03    1.43E+03    2.56E+06    2.16E+08    2.37E+05    2.57E+05    2.43E+05    2.65E+05    4.03E+05    4.43E+05
        5.11E+03    1.37E+03    1.24E+03    1.20E+03    1.21E+03    1.10E+03    1.28E+03    1.34E+03    3.09E+06    1.61E+08    2.84E+05    2.93E+05    2.91E+05    2.34E+05    5.40E+07    3.07E+05
        5.79E+03    2.51E+03    2.15E+03    2.21E+03    3.57E+03    1.67E+03    2.61E+03    2.28E+03    3.08E+06    4.98E+06    3.60E+06    1.63E+08    7.06E+06    1.95E+06    5.74E+07    3.44E+06
        4.49E+03    1.88E+03    1.22E+03    1.47E+03    1.23E+03    1.04E+03    1.42E+03    1.37E+03    6.11E+05    2.67E+06    2.93E+05    2.15E+08    3.31E+05    2.26E+05    4.13E+05    3.53E+05
        4.50E+03    2.22E+03    1.40E+03    1.34E+03    1.26E+03    1.22E+03    1.18E+03    1.35E+03    6.43E+05    1.10E+08    3.31E+05    1.07E+08    3.50E+05    3.29E+05    3.69E+05    4.26E+05

   

    c.csv:
        1.30E+06    4.34E+05    4.66E+04    0.00E+00    0.00E+00    0.00E+00    0.00E+00    0.00E+00    1.62E+08    5.65E+07    6.02E+06    3.24E+05    3.55E+05    2.83E+05    3.41E+05    4.05E+05
        0.00E+00    1.74E+06    0.00E+00    0.00E+00    0.00E+00    0.00E+00    0.00E+00    0.00E+00    5.61E+05    2.17E+08    3.12E+05    3.34E+05    2.83E+05    2.83E+05    3.01E+05    3.45E+05
        0.00E+00    1.74E+06    0.00E+00    0.00E+00    0.00E+00    0.00E+00    0.00E+00    0.00E+00    6.08E+05    2.17E+08    8.92E+05    3.47E+05    3.43E+05    2.22E+05    3.64E+05    2.38E+05
        0.00E+00    1.74E+06    0.00E+00    0.00E+00    0.00E+00    0.00E+00    0.00E+00    0.00E+00    5.61E+05    2.15E+08    2.90E+06    3.35E+05    3.08E+05    5.85E+05    3.60E+05    3.81E+05
        0.00E+00    1.74E+06    0.00E+00    0.00E+00    0.00E+00    0.00E+00    0.00E+00    0.00E+00    5.45E+05    2.15E+08    2.90E+06    3.11E+05    3.06E+05    2.88E+05    3.73E+05    3.10E+05
        0.00E+00    1.30E+06    0.00E+00    0.00E+00    0.00E+00    0.00E+00    0.00E+00    9.22E+04    4.90E+06    1.65E+08    8.92E+05    3.07E+06    1.37E+06    3.40E+06    1.53E+06    1.52E+07
        0.00E+00    1.74E+06    0.00E+00    4.69E+04    0.00E+00    0.00E+00    0.00E+00    0.00E+00    3.09E+06    2.15E+08    3.08E+05    6.15E+06    3.48E+05    3.63E+05    3.85E+05    4.12E+05
        0.00E+00    0.00E+00    0.00E+00    1.31E+06    0.00E+00    0.00E+00    4.36E+05    0.00E+00    3.06E+06    1.35E+06    2.31E+05    1.61E+08    2.89E+05    2.05E+05    5.41E+07    1.77E+06
        0.00E+00    0.00E+00    0.00E+00    1.74E+06    0.00E+00    0.00E+00    0.00E+00    0.00E+00    6.69E+05    2.27E+06    3.02E+05    2.16E+08    3.27E+05    3.08E+05    3.50E+05    3.75E+05
        0.00E+00    8.69E+05    0.00E+00    8.71E+05    0.00E+00    0.00E+00    0.00E+00    0.00E+00    6.68E+05    1.10E+08    3.07E+05    1.08E+08    3.67E+05    2.34E+05    3.71E+05    3.78

    Final expected output (after averaging column 8):
    5.42E+05    4.25E+03    1.30E+06    125650487
    4.64E+04    4.47E+03    0.00E+00    593233.3333
    4.36E+04    5.12E+03    0.00E+00    634780
    4.32E+04    4.32E+03    0.00E+00    570865
    4.44E+04    4.64E+03    0.00E+00    766418
    1.47E+05    5.03E+03    0.00E+00    3393342.667
    1.81E+05    5.11E+03    0.00E+00    3113608.333
    4.94E+05    5.79E+03    0.00E+00    6532673.333
    4.79E+04    4.49E+03    0.00E+00    630900.3333
    4.51E+04    4.50E+03    0.00E+00    636023

Then I was to do the looping for all the 16 columns (taking the following sets as[n,n+8] where n=0 to 7.

Apologize for the lengthy description, but I can't seem to append the columns in python.
Thanks in advance.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Here is a sample code I started with:

    import csv
    import numpy as np
    import sys
    import pandas as pd
    import glob
    damn = ("a", "b", "c","e","f","g","h","i")
    data = []
    
    for fles in range(len(damn)):
        core0data = np.genfromtxt('./%s_raw_combine.csv'%damn[fles], dtype=float, delimiter=',',usecols=(0,8))
        #core1data = np.genfromtxt('./%s_raw_combine.csv'%damn[fles], dtype=float, delimiter=',',usecols=(1,9))
        #core2data = np.genfromtxt('./%s_raw_combine.csv'%damn[fles], dtype=float, delimiter=',',usecols=(2,10))
        #core3data = np.genfromtxt('./%s_raw_combine.csv'%damn[fles], dtype=float, delimiter=',',usecols=(3,11))
        #core4data = np.genfromtxt('./%s_raw_combine.csv'%damn[fles], dtype=float, delimiter=',',usecols=(4,12))
        #core5data = np.genfromtxt('./%s_raw_combine.csv'%damn[fles], dtype=float, delimiter=',',usecols=(5,13))
        #core6data = np.genfromtxt('./%s_raw_combine.csv'%damn[fles], dtype=float, delimiter=',',usecols=(6,14))
        #core7data = np.genfromtxt('./%s_raw_combine.csv'%damn[fles], dtype=float, delimiter=',',usecols=(7,15))
        data.append(core0data)
        
    np.savetxt("writer.csv", data, delimiter= ",")

But after running this, I get error:

     > python2.7 new.py 
    Traceback (most recent call last):
      File "new.py", line 20, in <module>
        np.savetxt("writer.csv", data, delimiter= ",")
      File "~/anaconda/lib/python2.7/site-packages/numpy/lib/npyio.py", line 1083, in savetxt
        fh.write(asbytes(format % tuple(row) + newline))
    TypeError: float argument required, not numpy.ndarray

How are you doing your averaging? a# tells me nothing. ? + ? + ? = 125650487

@Corona688:
the average you see is: avg(a[8],b[8],c[8])

Ahhh. What you were calling column 8 I considered column 9.

I do not know python, and if I did, I probably wouldn't know all 5 modules you were using for this simple problem.

awk 'BEGIN {
        while(1)
        {
                A[ARGC]=0;
                for(N=1; (N<ARGC); N++)
                {
                        if((getline < ARGV[N]) <= 0) exit;
                        A[N]=$1;
                        A[ARGC] += $9;
                }

                A[ARGC]/=(ARGC-1);              P="";
                for(N=1; N<=ARGC; (N++) && (P="\t")) printf("%s%s", P, A[N]);
                printf("\n");
        }
}' a b c

5.42E+05        4.25E+03        1.30E+06        126000000
4.64E+04        4.47E+03        0.00E+00        593333
4.36E+04        5.12E+03        0.00E+00        635000
4.32E+04        4.32E+03        0.00E+00        570667
4.44E+04        4.64E+03        0.00E+00        767000
1.47E+05        5.03E+03        0.00E+00        3.39333e+06
1.81E+05        5.11E+03        0.00E+00        3.11333e+06
4.94E+05        5.79E+03        0.00E+00        6.54667e+06
4.79E+04        4.49E+03        0.00E+00        630667
4.51E+04        4.50E+03        0.00E+00        636000

$