title: Creating two lists from one randomly
body: <p>I'm using pandas to import a lot of data from a CSV file, and once read I format it to contain only numerical data. This then returns a list within a list. Each list then contains around 140k bits of data. <code>numericalData[][]</code>.</p>
  
  <p>From this list, I wish to create <code>Testing</code> and <code>Training Data</code>. For my testing data, I want to have 30% of my read data <code>numericalData</code>, so I use this following bit of code;</p>
  
  <pre><code>testingAmount = len(numericalData0[0]) * trainingDataPercentage / 100
  </code></pre>
  
  <p>Works a treat. Then, I use numpy to select that amount of data from each column of my imported <code>numericalData</code>;</p>
  
  <pre><code>testingData.append(np.random.choice(numericalData[x], testingAmount)  )      
  </code></pre>
  
  <p>This then returns a sample with 38 columns (running in a loop), where each column has around 49k elements of data randomly selected from my imported <code>numericalData</code>.</p>
  
  <p>The issue is, my <code>trainingData</code> needs to hold the other 70% of the data, but I'm unsure on how to do this. I've tried to compare each element in my <code>testingData</code>, and if both elements aren't equal, then add it to my <code>trainingData</code>. This resulted in an error and didn't work. Next, I tried to delete the selected <code>testingData</code> from my imported data, and then save that new column to my <code>trainingData</code>, alas, that didn't work eiher.</p>
  
  <p>I've only been working with python for the past week so I'm a bit lost on what to try now. </p>