title: Create new dataframe based on condition
body: <p>I have a series of csv files inside a directory. Each csv file has the following columns:</p>
  <p><code>slotID; NLunUn; NLunTot; MeanBPM</code></p>
  <p>I would like, starting from the values contained within the slotID column, to create data frames that contain the relative values. Eg
  the 1st csv has the following values:</p>
  <pre><code>slotID NLun An NLunTot MeanBPM
  7 11 78 129,7
  11 6 63 123,3
  12 6 33 120,6
  13 5 41 124,5
  14 4 43 118,9
  </code></pre>
  <p>the 2nd csv has the following values</p>
  <pre><code>slotID NMarAn NMarTot MeanBPM
  7 10 72 131,2
  11 5 48 121,5
  12 4 17 120,9
  13 4 19 125,6
  16 6 45 127,4
  </code></pre>
  <p>I would like to create a dataframe which for example is called dataframe1 which has the values of slot 7 inside, another csv which contains the values of slot 11 etc ... Any suggestion is welcome, I've been trying for several days but can't seem to jump out, please help me. This is what i've done so far:</p>
  <pre><code>import pandas as pd
  #import matplotlib.pyplot as plt 
  import os
  import glob
  import numpy as np
  
  path = os.getcwd()
  csv_files = glob.glob(os.path.join(path, &quot;*.csv&quot;))
  
  for f in csv_files:
      dfDay = pd.read_csv(f, encoding = &quot;ISO-8859-1&quot;, sep = ';')
      //inside dfday there are all the files that contain the data   
  </code></pre>