title: Python - TypeError: zip argument #1 must support iteration
body: <p>I have the following code:</p>
  
  <pre><code>import numpy as np
  import scipy as sp
  import itertools
  import os
  
  rootdir = 'mydir'; # mydir changed from actual directory
  
  data = []
  
  for i in range(1, 35):
      data = []
      chari = str(i)+'/';
      newdir = rootdir+chari
      print newdir
      for root, dirs, files in os.walk(newdir):
          for fname in files:
              if fname == 'tc.out':
                  with open(os.path.join(root,fname)) as f:
                      lines_after_2 = f.readlines()[2:]
                      for line in lines_after_2:
                          fields = line.split()
                          rowdata = map(float,fields)
                          data.extend(rowdata)
                          column = zip(*rowdata)
                          for index, column in enumerate(columns):
                              print "In column %s, Max = %s, Min = %s" % (index, max(column), min(column))
  </code></pre>
  
  <p>I am attempting to find the MAXIMUM and MINIMUM value per column (my real goal is to find the max and min for every column but the first, but I'll try to tackle that later).</p>
  
  <p>Upon running this code, I get the following error:</p>
  
  <pre><code>TypeError: zip argument #1 must support iteration
  </code></pre>
  
  <p>This is how my data is structured:</p>
  
  <pre><code>variables = time T_1 T_2 T_3 T_4 T_5
  # 5
  3.0100000000e+03  3.0349158928e+02 3.0171422239e+02 2.9770226435e+02 2.9657072961e+02 2.9707000000e+02
  3.0125798902e+03  3.0334549013e+02 3.0152263068e+02 2.9799460866e+02 2.9662883748e+02 2.9706572397e+02
  3.0175798902e+03  3.0324699921e+02 3.0138079877e+02 2.9821459880e+02 2.9667166944e+02 2.9706245240e+02
  3.0225798902e+03  3.0336015983e+02 3.0128802830e+02 2.9836039823e+02 2.9670134577e+02 2.9706003491e+02
  </code></pre>
  
  <p>I'm attempting to skip over the first two lines, then read the columns and pick out the max and min values.</p>
  
  <p>What's going on here?</p>