title: Add columns to one pandas dataframe to another with condition
body: <p>Dataframe 1:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>i</th>
  <th>a</th>
  <th>b</th>
  <th>c</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>1</td>
  <td>foo</td>
  <td>1</td>
  <td>3</td>
  </tr>
  <tr>
  <td>2</td>
  <td>foo</td>
  <td>1</td>
  <td>3</td>
  </tr>
  <tr>
  <td>3</td>
  <td>bar</td>
  <td>1</td>
  <td>3</td>
  </tr>
  <tr>
  <td>4</td>
  <td>foo</td>
  <td>1</td>
  <td>3</td>
  </tr>
  <tr>
  <td>5</td>
  <td>foo</td>
  <td>1</td>
  <td>3</td>
  </tr>
  <tr>
  <td>6</td>
  <td>baz</td>
  <td>1</td>
  <td>3</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>Dataframe 2:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>i</th>
  <th>1</th>
  <th>2</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>1</td>
  <td>foo</td>
  <td>i'm foo</td>
  </tr>
  <tr>
  <td>2</td>
  <td>bar</td>
  <td>i'm bar</td>
  </tr>
  <tr>
  <td>3</td>
  <td>baz</td>
  <td>i'm baz</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>Resulting Dataframe1:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>i</th>
  <th>a</th>
  <th>b</th>
  <th>c</th>
  <th>new column</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>1</td>
  <td>foo</td>
  <td>1</td>
  <td>3</td>
  <td>i'm foo</td>
  </tr>
  <tr>
  <td>2</td>
  <td>foo</td>
  <td>1</td>
  <td>3</td>
  <td>i'm foo</td>
  </tr>
  <tr>
  <td>3</td>
  <td>bar</td>
  <td>1</td>
  <td>3</td>
  <td>i'm bar</td>
  </tr>
  <tr>
  <td>4</td>
  <td>foo</td>
  <td>1</td>
  <td>3</td>
  <td>i'm foo</td>
  </tr>
  <tr>
  <td>5</td>
  <td>foo</td>
  <td>1</td>
  <td>3</td>
  <td>i'm foo</td>
  </tr>
  <tr>
  <td>6</td>
  <td>baz</td>
  <td>1</td>
  <td>3</td>
  <td>i'm baz</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>Hello guys, I couldn't find the answer to this specific problem, Hope you guys can help.
  I want to append column from dataframe2 to dataframe1 depending on this condition:</p>
  <p>If dataframe1 column 'a' matches with dataframe2 column '1', append dataframe2 column '2' to dataframe1</p>
  <p>I can try iterating both dataframes and fill in the values but that would not be efficient at all.</p>
  <p>Awaiting your responses, Let me know if I missed any detail.</p>
  <p>Thank you</p>