title: list comprehension and lambda expression in python 2.6 vr. python 2.7
body: <p>I am trying to back-port code written for python 2.7 into python 2.6 (the reason is that the server where the code is supposed to run has only python 2.6 and the admin refuses to install python 2.7 or higher).</p>
  
  <p>In general this worked fine, but I found the following problem. In the original code the lines (or something similar):</p>
  
  <pre><code>g = lambda x : ['{:d}'.format(i) for i in x]
  g([1,2,3,4])
  </code></pre>
  
  <p>worked fine. However, in python 2.6 they produce an error. I couldn't find anything about this  topic on the documentation.</p>
  
  <p>What is the reason? Is there any simple solution to this problem, i.e., a definition of the lambda expression that is equivalent (same semantics) but uses different syntax?</p>