title: Read .dat file using python
body: <p>I've got a simulation involving internal waves and moving particles in the water, using the <em>MITgcm</em>. The output of this looks something like this for each time step:</p>
  
  <pre><code>   -9999 0.0000000000000000000  #Time step (0.00000000000000 seconds)
   1308.2021183321899       -14.999709364517091 # Particle 1 (X,Z)
   1308.2020142528656       -24.999521595698688 # Particle 2 (X,Z)
   1308.2018600072618       -34.999345597877536 # .
   1308.2016593336587       -44.999185870669805 # .
   1308.2014165588744       -54.999046508237896 # .
   1308.2011370083103       -64.998931076248894
   1308.2008269116873       -74.998842490305705
   1308.2004933548124       -84.998782925797485
   1308.2001441978532       -94.998753764086956
   1308.1997879652938       -104.99875557384759
   1308.1994336881464       -114.99878812280582
   1308.1990906721119       -124.99885041328211
   1308.1987681881285       -134.99894073461562
   1308.1984750963150       -144.99905672694641
   1308.1982194336249       -154.99919545294702
   1308.1980080134056       -164.99935347476733
   1308.1978461242272       -174.99952693694112
   1308.1977378137256       -184.99971163492469
   1308.2000000000000       -195.00000000000000
   5232.8000000000002       -15.000038916290352
   5232.8000000000002       -25.000064153684303
   5232.8000000000002       -35.000089286157163
   5232.8000000000002       -45.000114270293523
   5232.8000000000002       -55.000139061712051 # Particle 57
  </code></pre>
  
  <p>Where -9999 #number is the time step (in seconds), left column is X position and right column is Z position (in meters); and every line is a different particle (except the -9999 one). So we'll have an enormous amount of lines with something like this for every time step and every particle.</p>
  
  <p>I would like to plot the time-evolution of the position of my particles. How can I do it? If that's too hard, I would be happy with static plots of different time-steps with all particles position.</p>
  
  <p>Thank you so much.</p>
  
  <p>Edit1: What I tried to do is this, but I didn't show it before because it is far from proper:</p>
  
  <pre><code> from matplotlib import numpy
   import matplotlib.pyplot as plot
   plot.plot(*np.loadtxt('data.dat',unpack=True), linewidth=2.0)
  </code></pre>
  
  <p>or this:</p>
  
  <pre><code> plot.plotfile('data.dat', delimiter=' ', cols=(0, 1), names=('col1', 'col2'), marker='o')
  </code></pre>