title: How to sum up a column in numpy
body: <p>i got a dataframe which i convert in an array (that is a testscenario because i have problems with the results in pandas). Now i want to sum up one column.</p>
  <p>I have the following code:</p>
  <pre><code>import sys
  import pandas as pd
  import numpy as np
  import os
  from tkinter import *
  
  
  #data_rbu = np.genfromtxt('tmp_fakt_daten.csv', delimiter=',', dtype=None)
  data_rbu = pd.read_excel('tmp_fakt_daten.xlsx')
  array_rbu = data_rbu.as_matrix()
  print(array_rbu)
  summe1 = np.sum(array_rbu, axis=9, dtype=float)
  print(summe1)
  </code></pre>
  <p>This is the Array! I want to sum up KW_WERT and NETTO_EURO.</p>
  <p>After executing the code i get this error:</p>
  <pre><code>Traceback (most recent call last):
    File &quot;C:\Users\----------\[INPROGRESS] Faktura_sylvia\csv_einlesen bzgl. float\test2.py&quot;, line 12, in &lt;module&gt;
      summe1 = np.sum(array_rbu, axis=9, dtype=float)
    File &quot;C:\Users\---------\Winpython\python-3.4.3\lib\site-packages\numpy\core\fromnumeric.py&quot;, line 1724, in sum
      out=out, keepdims=keepdims)
    File &quot;C:\Users\----------\Winpython\python-3.4.3\lib\site-packages\numpy\core\_methods.py&quot;, line 32, in _sum
      return umr_sum(a, axis, dtype, out, keepdims)
  ValueError: 'axis' entry is out of bounds
  </code></pre>
  <p>I understand that the problem is the axis number.. but i dont know what im exactly doing wrong. I checked the documentation for numpy.sum...</p>
  <p>Hope you can help me!</p>
  <p>Damian</p>