title: How to replace single value in pandas dataframe by index
body: <p>Below is an example of what I want to do. Basically I know the index and the column of the value I want to replace and just want to replace a specific cell. No conditional statements.</p>
  <pre class="lang-py prettyprint-override"><code>
  df_a = pd.DataFrame(data={&quot;a&quot;: [0, 0, 0], &quot;b&quot;: [0, 0, 0]})
  display(df_a)
  
      a   b
  0   0   0
  1   0   0
  2   0   0
  
  df_b = pd.DataFrame(data={&quot;a&quot;: [0, 0, 10], &quot;b&quot;: [0, 0, 0]})
  
      a   b
  0   0   0
  1   0   0
  2   10  0
  </code></pre>