title: How to subtract every first column value form every other values from a file?
body: <p>I have a file which has a content like below</p>
  
  <pre><code>14.678  14.652  14.636  14.623  14.615  14.608  14.603  14.599  14.596
  17.448  17.427  17.413  17.402  17.395  17.390  17.386  17.384  17.382
  18.271  18.252  18.240  18.231  18.223  18.217  18.212  18.211  18.209
  20.239  20.216  20.198  20.188  20.168  20.164  20.165  20.147  20.125
  20.500  20.480  20.458  20.438  20.421  20.400  20.382  20.368  20.355
  17.195  17.173  17.159  17.150  17.143  17.138  17.134  17.132  17.130
  18.652  18.628  18.611  18.600  18.590  18.583  18.580  18.571  18.565
  18.721  18.697  18.684  18.673  18.665  18.656  18.648  18.645  18.644
  19.501  19.452  19.396  19.314  19.166  18.936  18.629  18.325  18.089
  18.470  18.449  18.434  18.421  18.413  18.406  18.401  18.399  18.397
  18.288  18.266  18.254  18.245  18.237  18.232  18.229  18.228  18.227
  18.691  18.669  18.653  18.641  18.631  18.622  18.614  18.612  18.606
  17.407  17.387  17.375  17.366  17.360  17.355  17.352  17.349  17.348
  16.691  16.672  16.659  16.649  16.643  16.639  16.635  16.632  16.631
  19.293  19.271  19.253  19.244  19.233  19.226  19.218  19.209  19.201
  18.530  18.509  18.493  18.482  18.474  18.469  18.463  18.457  18.452
  18.769  18.742  18.725  18.712  18.701  18.695  18.688  18.682  18.681
  18.356  18.335  18.320  18.310  18.300  18.294  18.288  18.283  18.281
  18.332  18.313  18.298  18.286  18.280  18.276  18.271  18.267  18.265
  14.998  14.977  14.963  14.953  14.945  14.940  14.936  14.933  14.930
  </code></pre>
  
  <p>I want to delete every first column value from every other values.The operation should be something like this</p>
  
  <pre><code>14.678 - 17.448
  14.678 - 18.271
  14.678 - 18.271
  and so on...
  </code></pre>
  
  <p>Similarly</p>
  
  <pre><code>17.448 - 14.678
  17.448 - 18.271
  17.448 - 20.239
  and so on...
  </code></pre>
  
  <p>So far what I am able to do is</p>
  
  <pre><code>with open("geodata.txt", "r") as fo:
      for i in fo:
          for j in fo:
              print(float(i.split(" ")[0]) - float(j.split(" ")[0]))
  </code></pre>
  
  <p>But it only does the operation one time and then it stops.</p>
  
  <pre><code>-2.7699999999999996
  -3.593
  -5.561
  -5.821999999999999
  -2.5169999999999995
  -3.974
  -4.042999999999999
  -4.823
  -3.791999999999998
  -3.6099999999999994
  -4.012999999999998
  -2.728999999999999
  -2.012999999999998
  -4.614999999999998
  -3.8520000000000003
  -4.0909999999999975
  -3.678000000000001
  -3.654
  -0.3199999999999985
  </code></pre>
  
  <p>I tried adding a while loop to do this operation 20 times (there are 20 rows) but the calculation takes forever.How can I achieve this?</p>