title: Correlation between 2 python lists
body: <p>I would like to correlate 2 lists like this:</p>
  
  <pre><code>a=[1337687805.49052, 1337687808.560519, 1337687813.06552, 1337687814.602522,
     1337687817.16352, 1337687823.836521, 1337687831.942522, 1337687837.931519, 
     1337687839.760519, 1337694258.54652, 1337709019.39452, 1337712024.05452, 
     1337714200.05952, 1337714903.08152, 1337721205.97952, 1337721207.05052, 
     1337723273.93052]
  
  b=[1337687803.533521, 1337688287.44452, 1337689866.760521, 1337689866.76352,
     1337690758.328521, 1337691231.61552, 1337691261.578519, 1337691261.68752,
     1337691362.20652, 1337691362.51652, 1337691366.431521, 1337691369.55252,
     1337691369.992521, 1337691387.000521, 1337691391.50552, 1337691406.192519, 
     1337691407.79952, 1337691411.74352, 1337691420.308521, 1337691422.035521, 
     1337691426.60752, 1337691426.753521, 1337691431.44952, 1337691437.87152, 
     1337691438.66452, 1337691448.45452, 1337691450.15852, 1337691451.49252, 
     1337691454.335519, 1337691459.87152, 1337691461.01652, 1337691480.819519, 
     1337691482.980521, 1337691484.914522, 1337691500.15652, 1337691514.32752]
  </code></pre>
  
  <p>a and b contains the epoch time of some events, so I need the correlation between a and b, do some significant graphs, maybe the correlation coefficient is useful too.
  The goal is to compare a lot of vectors a,b,c,d,... with different timestamps in order to know if they had a similar behavior.</p>