title: Python: nested 'for' loops
body: <p>I'd like to go through all n-digit numbers such that second digit of the number is always lower or equal to the first, third is lower or equal to the second etc. I can get this by writing a horrible code such as:</p>
  
  <pre><code>for i in range(10):
      for j in range(i+1):
          for k in range(j+1):
  </code></pre>
  
  <p>etc., but with 10-digit numbers my code starts looking horrible, and also that's a lot of writing, and indentation get horrible if I want to commend few of those. Is there a nice, concise way of getting this?</p>
  
  <p>Edit: just so that people know why I'm bothering with this, <a href="https://projecteuler.net/problem=74">https://projecteuler.net/problem=74</a> has me check numbers from 1 to one milion. Unfortunately, It's not as straightforward as I thought -- numbers with leading zeros are treated differently than the ones with zeros inside, so some additional magic had to be performed. Anyway, thanks to all for insightful suggestions.</p>