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POWhen to drop list Comprehension and the Pythonic way?
 

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  1. POWhen to drop list Comprehension and the Pythonic way?
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    <p>I created a line that appends an object to a list in the following manner</p> <pre><code>&gt;&gt;&gt; foo = list() &gt;&gt;&gt; def sum(a, b): ... c = a+b; return c ... &gt;&gt;&gt; bar_list = [9,8,7,6,5,4,3,2,1,0] &gt;&gt;&gt; [foo.append(sum(i,x)) for i, x in enumerate(bar_list)] [None, None, None, None, None, None, None, None, None, None] &gt;&gt;&gt; foo [9, 9, 9, 9, 9, 9, 9, 9, 9, 9] &gt;&gt;&gt; </code></pre> <p>The line </p> <pre><code>[foo.append(sum(i,x)) for i, x in enumerate(bar_list)] </code></pre> <p>would give a pylint W1060 Expression is assigned to nothing, but since I am already using the foo list to append the values I don't need to assing the List Comprehension line to something.</p> <p><strong>My questions is more of a matter of programming correctness</strong></p> <p>Should I drop list comprehension and just use a simple for expression?</p> <pre><code>&gt;&gt;&gt; for i, x in enumerate(bar_list): ... foo.append(sum(i,x)) </code></pre> <p>or is there a correct way to use both list comprehension an assign to nothing?</p> <p><strong>Answer</strong></p> <p>Thank you @user2387370, @kindall and @Martijn Pieters. For the rest of the comments I use append because I'm not using a list(), I'm not using i+x because this is just a simplified example. </p> <p>I left it as the following:</p> <pre><code>histogramsCtr = hist_impl.HistogramsContainer() for index, tupl in enumerate(local_ranges_per_histogram_list): histogramsCtr.append(doSubHistogramData(index, tupl)) return histogramsCtr </code></pre>
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    1. USClaudiordgz
    1. USClaudiordgz
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    1. COI realize this is just an example, but why append at all? Why not just `foo = [sum(i, x) ...]`?
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      1. USDaniel Roseman
    2. CO`sum(i, x)` doesn't work. Do you mean `i + x`?
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      1. USuser2357112
    3. COIf you really want a 1-liner, you can put a `for` loop on one line. Not recommended, though.
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      1. POWhen to drop list Comprehension and the Pythonic way?
      1. USuser2357112
 

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