title: How set a particular cell value in pandas?
body: <p>I am trying to set a value in panda dataframe.</p>
  
  <pre><code>ZEROS = np.zeros((4,4), dtype=np.int)
  
  df = pd.DataFrame(ZEROS,  columns=['A1','B1','C1','D1'])
  df.at[2,3] = 32
  df
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/arkbI.png" rel="noreferrer"><img src="https://i.stack.imgur.com/arkbI.png" alt="enter image description here"></a></p>
  
  <p>I don't want <code>NaN</code> for the entire column, the expected output is below:</p>
  
  <p>Using numpy  I am able to set the value like below</p>
  
  <pre><code>ZEROS[1][3] = 44
  </code></pre>
  
  <p>output:</p>
  
  <pre><code>array([[ 0,  0,  0,  0],
         [ 0,  0,  0, 44],
         [ 0,  0,  0,  0],
         [ 0,  0,  0,  0]])
  </code></pre>