title: Creating an element-wise minimum Series from two other Series in Python Pandas
body: <p>I am having trouble finding a way to do an efficient element-wise minimum of two Series objects in pandas. For example I can add two Series easily enough:</p>
  
  <pre><code>In [1]:
  import pandas as pd
  s1 = pd.Series(data=[1,1,1], index=[1,2,3])
  s2 = pd.Series(data=[1,2,2,1], index=[1,2,3,4])
  s1.add(s2)    
  Out[1]:
  1     2
  2     3
  3     3
  4   NaN
  dtype: float64
  </code></pre>
  
  <p>But I cannot find an efficient way to do an element-wise minimum between two Series (along with aligning the indices and handling NaN values).</p>
  
  <p><em>Nevermind. There is an escape hatch with the combine function so you can put in any element-wise function:</em></p>
  
  <pre><code>In [2]:
  s1 = pd.Series(data=[1,1,1], index=[1,2,3])
  s2 = pd.Series(data=[1,2,2,1], index=[1,2,3,4])
  s1.combine(s2, min, 0)
  Out[2]:
  1    1
  2    1
  3    1
  4    0
  dtype: int64
  </code></pre>