title: Compare two dataframes based off of key
body: <p>I have two dataframes, df1 and df2, which have the exact same columns and most of the time the same values for each key.</p>
  
  <blockquote>
  <pre><code>Country   A   B   C   D   E   F   G   H   Key
  Argentina xylo    262 4632    0   0   26.12   2   0   Argentinaxylo
  Argentina phone   6860    155811  48  0   4375.87 202 0   Argentinaphone
  Argentina land    507 1803728 2   117 7165.810566 3   154 Argentinaland
  Australia xylo    7650    139472  69  0   16858.42    184 0   Australiaxylo
  Australia mink    1284    2342788 1   0   39287.71    53  0   Australiamink
  
  
  Country   A   B   C   D   E   F   G   H   Key
  Argentina xylo    262 4632    0   0   26.12   2   0   Argentinaxylo
  Argentina phone   6860    155811  48  0   4375.87 202 0   Argentinaphone
  Argentina land    507 1803728 2   117 7165.810566 3   154 Argentinaland
  Australia xylo    7650    139472  69  0   16858.42    184 0   Australiaxylo
  Australia mink    1284    2342788 1   0   39287.71    53  0   Australiamink
  </code></pre>
  </blockquote>
  
  <p>I want a snippet that compares the keys (key = column Country + column A) in each dataframe against each other and calculates the percent difference for each column B-H, if there is any. If there isn't, output nothing.</p>