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copied!<blockquote> <p>Eine Minuten bitte, Ich hap eine kleine Problemo avec diese Religione. -- Eddie Izzard (doing his impression of Martin Luther)</p> </blockquote> <p>Deleting by reverse-iterating over a list to preserve the iterator <em>is</em> a common solution to this problem. But another solution is to change this into a different problem. Instead of deleting items from the list using some criteria (in your case, the index exists in a list of indexes to be deleted), create a new list that leaves out the offending items.</p> <pre><code>L[:] = [ item for i,item in enumerate(L) if i not in I ] </code></pre> <p>For that matter, where did you come up with the indexes in <code>I</code> in the first place? You could combine the logic of getting the indexes to be removed and building the new list. Assuming this is a list of objects and you only want to keep those that pass an <code>isValid</code> test:</p> <pre><code>L[:] = [ item for item in L if item.isValid() ] </code></pre> <p>This is much more straightforward than:</p> <pre><code>I = set() for i in range(len(L)): if not L[i].isValid(): I.add(i) for i in sorted(I, reverse=True): del L[i] </code></pre> <p>For the most part, I turn any question about "how to delete from a list the items that I don't want" into "how to create a new list containing just the items I want".</p> <p>EDITED: changed "L = ..." to "L[:] = ..." per Alex Martelli's answer to <a href="https://stackoverflow.com/questions/1352885/remove-elements-as-you-traverse-a-list-in-python">this question</a>.</p>

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