title: Split pandas dataframe into multiple dataframes with equal numbers of rows
body: <p>I have a dataframe <code>df</code> :</p>
  
  <pre><code>        a              b          c
  0   0.897134    -0.356157   -0.396212
  1   -2.357861   2.066570    -0.512687
  2   -0.080665   0.719328    0.604294
  3   -0.639392   -0.912989   -1.029892
  4   -0.550007   -0.633733   -0.748733
  5   -0.712962   -1.612912   -0.248270
  6   -0.571474   1.310807    -0.271137
  7   -0.228068   0.675771    0.433016
  8   0.005606    -0.154633   0.985484
  9   0.691329    -0.837302   -0.607225
  10  -0.011909   -0.304162   0.422001
  11  0.127570    0.956831    1.837523
  12  -1.074771   0.379723    -1.889117
  13  -1.449475   -0.799574   -0.878192
  14  -1.029757   0.551023    2.519929
  15  -1.001400   0.838614    -1.006977
  16  0.677216    -0.403859   0.451338
  17  0.221596    -0.323259   0.324158
  18  -0.241935   -2.251687   -0.088494
  19  -0.995426   0.665569    -2.228848
  20  1.714709    -0.353391   0.671539
  21  0.155050    1.136433    -0.005721
  22  -0.502412   -0.610901   1.520165
  23  -0.853906   0.648321    1.124464
  24  1.149151    -0.187300   -0.412946
  25  0.329229    -1.690569   -2.746895
  26  0.165158    0.173424    0.896344
  27  1.157766    0.525674    -1.279618
  28  1.729730    -0.798158   0.644869
  29  -0.107285   -1.290374   0.544023
  </code></pre>
  
  <p>that I need to split into multiple dataframes that will contain every 10 rows of <code>df</code> , and every small dataframe I will write to separate file. so  I decided create multilevel dataframe, and for this first assign the index to every 10 rows in my <code>df</code> with this method:</p>
  
  <pre><code>df['split'] = df['split'].apply(lambda x: np.searchsorted(df.iloc[::10], x, side='right')[0])
  </code></pre>
  
  <p>that throws out </p>
  
  <pre><code>TypeError: 'function' object has no attribute '__getitem__'
  </code></pre>
  
  <p>So, do you have an idea of how to fix it? Where is my method wrong?</p>
  
  <p>But if you have another approach to split my dataframe into multiple dataframes every of which contains 10 rows of <code>df</code>, you are also welcome, cause this approach was just the first I thought about, but I'm not sure that it's the best one.</p>