title: Finding the median of a histogram
body: <p>A have a dataframe like this which represents a histogram, with each bin size being .003.  I want to find the median value in the histogram, but I am unsure how.  The median should be where half of the area of the histogram lies to the left, and half of the area to the right.  </p>
  
  <pre><code>    Count Value
      0     0.262584
      0     0.265584
      0     0.268584
      1     0.271584
      1     0.274584
      2     0.277584
      2     0.280584
      1     0.283584
      0     0.286584
      3     0.289584
      3     0.292584
      10    0.295584
      7     0.298584
      22    0.301584
      2     0.304584
      17    0.307584
      19    0.310584
      19    0.313584
      32    0.316584
      17    0.319584
      17    0.322584
      25    0.325584
      32    0.328584
      18    0.331584
      24    0.334584
      43    0.337584
      38    0.340584
      30    0.343584
      21    0.346584
      53    0.349584
      45    0.352584
      36    0.355584
      46    0.358584
      58    0.361584
      34    0.364584
      71    0.367584
      50    0.370584
      73    0.373584
      60    0.376584
      97    0.379584
      67    0.382584
      84    0.385584
      70    0.388584
      106   0.391584
      91    0.394584
      148   0.397584
      70    0.400584
      166   0.403584
      88    0.406584
      155   0.409584
      126   0.412584
      128   0.415584
      181   0.418584
      81    0.421584
      216   0.424584
      95    0.427584
      193   0.430584
      67    0.433584
      164   0.436584
      68    0.439584
      133   0.442584
      60    0.445584
      92    0.448584
      38    0.451584
      63    0.454584
      40    0.457584
      43    0.460584
      24    0.463584
      32    0.466584
      19    0.469584
      11    0.472584
      11    0.475584
      13    0.478584
      4     0.481584
      6     0.484584
      3     0.487584
      5     0.490584
      3     0.493584
      4     0.496584
      5     0.499584
      1     0.502584
      3     0.505584
      1     0.508584
      1     0.511584
      1     0.514584
      0     0.517584
      1     0.520584
      3     0.523584
      0     0.526584
      0     0.529584
      0     0.532584
      0     0.535584
      0     0.538584
      1     0.541584
      1     0.544584
      3     0.547584
      0     0.550584
      0     0.553584
      0     0.556584
      1     0.559584
      0     0.562584
      0     0.565584
      0     0.568584
      1     0.571584
      0     0.574584
      0     0.577584
      0     0.580584
      1     0.583584
      0     0.586584
      1     0.589584
  </code></pre>
  
  <p>My histogram looks like this:</p>
  
  <p><a href="https://i.stack.imgur.com/zdwhR.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/zdwhR.jpg" alt="enter image description here"></a></p>
  
  <p>and the code I am using to find the median is this:</p>
  
  <pre><code>import pandas as pd
  import numpy as np
  df=pd.read_csv(r'C:\file')
  list1=df['Value'].tolist()
  median = np.median(list1)
  print median
  </code></pre>
  
  <p>which returns 0.42758.</p>
  
  <p>I am not sure if this is the correct method even though this value looks reasonable, so I wanted to see what peoples thoughts were here.</p>
  
  <p>EDIT:</p>
  
  <p>This is clearly not the correct method. Here is another example where it doesn't work:</p>
  
  <pre><code>1   0.283396
  0   0.286396
  0   0.289396
  0   0.292396
  0   0.295396
  3   0.298396
  0   0.301396
  0   0.304396
  0   0.307396
  0   0.310396
  0   0.313396
  1   0.316396
  0   0.319396
  0   0.322396
  0   0.325396
  1   0.328396
  1   0.331396
  2   0.334396
  0   0.337396
  0   0.340396
  1   0.343396
  5   0.346396
  0   0.349396
  1   0.352396
  0   0.355396
  0   0.358396
  0   0.361396
  1   0.364396
  0   0.367396
  1   0.370396
  1   0.373396
  2   0.376396
  0   0.379396
  1   0.382396
  0   0.385396
  0   0.388396
  1   0.391396
  0   0.394396
  1   0.397396
  1   0.400396
  3   0.403396
  4   0.406396
  0   0.409396
  3   0.412396
  0   0.415396
  3   0.418396
  2   0.421396
  5   0.424396
  1   0.427396
  3   0.430396
  8   0.433396
  1   0.436396
  2   0.439396
  1   0.442396
  4   0.445396
  4   0.448396
  5   0.451396
  1   0.454396
  7   0.457396
  8   0.460396
  4   0.463396
  5   0.466396
  9   0.469396
  4   0.472396
  5   0.475396
  6   0.478396
  11  0.481396
  4   0.484396
  4   0.487396
  6   0.490396
  6   0.493396
  10  0.496396
  14  0.499396
  7   0.502396
  10  0.505396
  7   0.508396
  9   0.511396
  8   0.514396
  3   0.517396
  12  0.520396
  9   0.523396
  9   0.526396
  11  0.529396
  8   0.532396
  9   0.535396
  15  0.538396
  9   0.541396
  7   0.544396
  10  0.547396
  6   0.550396
  12  0.553396
  9   0.556396
  7   0.559396
  6   0.562396
  5   0.565396
  11  0.568396
  7   0.571396
  12  0.574396
  8   0.577396
  8   0.580396
  6   0.583396
  9   0.586396
  9   0.589396
  18  0.592396
  10  0.595396
  14  0.598396
  16  0.601396
  14  0.604396
  16  0.607396
  12  0.610396
  19  0.613396
  18  0.616396
  25  0.619396
  22  0.622396
  20  0.625396
  16  0.628396
  22  0.631396
  18  0.634396
  26  0.637396
  26  0.640396
  18  0.643396
  26  0.646396
  39  0.649396
  31  0.652396
  31  0.655396
  37  0.658396
  35  0.661396
  46  0.664396
  49  0.667396
  47  0.670396
  43  0.673396
  46  0.676396
  53  0.679396
  52  0.682396
  47  0.685396
  49  0.688396
  67  0.691396
  58  0.694396
  61  0.697396
  52  0.700396
  74  0.703396
  79  0.706396
  81  0.709396
  62  0.712396
  73  0.715396
  97  0.718396
  73  0.721396
  107 0.724396
  98  0.727396
  89  0.730396
  96  0.733396
  85  0.736396
  97  0.739396
  102 0.742396
  103 0.745396
  126 0.748396
  113 0.751396
  112 0.754396
  134 0.757396
  126 0.760396
  107 0.763396
  120 0.766396
  120 0.769396
  135 0.772396
  153 0.775396
  143 0.778396
  132 0.781396
  145 0.784396
  119 0.787396
  124 0.790396
  155 0.793396
  99  0.796396
  117 0.799396
  127 0.802396
  126 0.805396
  102 0.808396
  118 0.811396
  76  0.814396
  92  0.817396
  75  0.820396
  72  0.823396
  59  0.826396
  42  0.829396
  49  0.832396
  33  0.835396
  38  0.838396
  24  0.841396
  12  0.844396
  5   0.847396
  15  0.850396
  4   0.853396
  6   0.856396
  4   0.859396
  2   0.862396
  2   0.865396
  1   0.868396
  0   0.871396
  2   0.874396
  1   0.877396
  </code></pre>
  
  <p>the histogram looks like this:</p>
  
  <p><a href="https://i.stack.imgur.com/g4csJ.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/g4csJ.jpg" alt="enter image description here"></a></p>
  
  <p>and the median value is this:</p>
  
  <p>.581896 which is clearly not the value where half the area lies to the right and half to the left. It is probably somewhere around .7 in this example.</p>