title: import and plot data from multiple files without too many lines
body: <p>I wrote a code that imports columns from a text file and plots them like this:</p>
  
  <pre><code>import os
  import numpy as np
  import matplotlib.pyplot as plt
  
  dataset = np.genfromtxt(fname='filename.dat')
  x=dataset[:,3]  # column select
  y=dataset[:,2] 
  
  plt.semilogx()
  #plt.semilogy()
  plt.xlabel('x')
  plt.ylabel('y')
  plt.title ('title')
  
  plt.plot(x, y, color='red', linewidth=1)  
  plt.show() 
  </code></pre>
  
  <p>The problem is that I would plot many more filename.dat (always columns 3 and 2 in every filename.dat).
  At the moment I have 23 filename.dat that I would like to plot all together in the same plot. These filename.dat are named as:</p>
  
  <pre><code>filename01.dat
  filename02.dat
  ...
  filename23.dat
  </code></pre>
  
  <p>I know I could rewrite the lines:</p>
  
  <pre><code>dataset_ = np.genfromtxt(fname='filename_.dat')
  x_=dataset_[:,3] 
  y_=dataset_[:,2]
  # where '_' is the number of each filename.dat
  plt.plot(x_, y_, color='red', linewidth=1) 
  </code></pre>
  
  <p>For each filename.dat, but is there a faster and more practical way (with np.genfromtxt and put.plot) to not rewrite the same lines for 23 times?</p>
  
  <p>UPDATE: I would also like a different color for each file.</p>