title: A method to remove duplicates from a multi dimensional array by comparing specific values
body: <p>I am writing a python script for data preprocessing. The data in question is read and stored within the script as a multi dimensional array consisting of data points similar to the ones below. </p>
  
  <pre><code>[['United', '-27.654379', '152.917741', 'e10', '1459', '2019-03-18'],
  ['United', '-27.654379', '152.917741', 'e10', '1449', '2019-03-19']]
  </code></pre>
  
  <p>Currently i need too remove values within the array that have identical dates so that</p>
  
  <pre><code>[['Costco', '-27.213607', '152.996416', 'e10', '1237', '2019-03-16'],
  ['United', '-25.607894', '150.367213', 'e10', '1297', '2019-03-16']]
  </code></pre>
  
  <p>Would become</p>
  
  <pre><code>[['Costco', '-27.213607', '152.996416', 'e10', '1237', '2019-03-16']]
  </code></pre>
  
  <p>My current method of doing so (shown below) appears to identify and remove entries with duplicate dates, but some can still be found within the output. </p>
  
  <pre class="lang-py prettyprint-override"><code>    for line in Data_text:
          for row in Data_text:
              if line[5] == row[5]:
                  Data_text.remove(row)
  </code></pre>
  
  <p>Any insight into the faults in my algorithm and/or a better way of doing it would be greatly appreciated. </p>