title: How to add rows with specific values to a dataframe in python
body: <p>Let's say I have the following df consisting of x values and their probabilities starting with x=19 and ending with x=64. </p>
  
  <pre><code>
        x    probability
  0   19.0    1.000000
  1   20.0    1.000000
  2   21.0    1.000000
  3   22.0    1.000000
  ...
  40  60.0    0.000000
  41  62.0    0.500000
  42  63.0    1.000000
  43  64.0    0.000000
  </code></pre>
  
  <p>What I would like to do is add rows ranging from x=65 to x=100 and have all of their probabilities be equal to 0, like so:</p>
  
  <pre><code>
        x     probability
  0   19.0     1.000000
  1   20.0     1.000000
  2   21.0     1.000000
  3   22.0     1.000000
  4   23.0     1.000000
  ...
  43  64.0     0.000000
  44  65.0     0.000000
  43  66.0     0.000000
  44  67.0     0.000000
  ...
  73  97.0     0.000000
  78  98.0     0.000000
  79  99.0     0.000000
  80  100.0    0.000000
  </code></pre>
  
  <p>Again, I would simply like to add consecutive x values from 65 to 100 with a probability of 0. I'm not quite sure how to add rows like this, so any help is appreciated. Thanks!</p>
  
  <p>Note: This question is similar to <a href="https://stackoverflow.com/questions/61501074/add-specific-number-of-rows-to-dataframe-python">add specific number of rows to dataframe (python)</a>, but I want my values in the column x to increase by 1 each time instead of stay the same.</p>