title: Check if the digits in the number are in increasing sequence in python
body: <p>I was working on a problem that determines whether the digits in the numbers are in the increasing sequence. Now, the approach I took to solve the problem was, For instance, consider the number 5678. </p>
  
  <p>To check whether 5678 is an increasing sequence, I took the first digit and the next digit and the last digit which is <code>5,6,8</code> and substitute in range function  <code>range(first,last,(diff of first digit and the next to first digit))</code> i.e <code>range(5,8+1,abs(5-6))</code>.The result is the list of digits in the ascending order</p>
  
  <p>To this problem, there is a constraint saying </p>
  
  <p><code>For incrementing sequences, 0 should come after 9, and not before 1, as in 7890.</code> Now my program breaks at the input 7890. I don't know how to encode this logic. Can someone help me, please?.</p>
  
  <p>The code for increasing sequence was </p>
  
  <pre><code>  len(set(['5','6','7','8']) - set(map(str,range(5,8+1,abs(5-6))))) == 0 
  </code></pre>