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    <p>There's a lot of answers here :)</p> <p>The two best answers (performance and clean code in one line) are the answers of @icecrime and @Hoopdady</p> <p>Both asnwers results equally, the only difference is performance.</p> <pre><code>cases = [ (None, 'testB'), ('', 'testB'), ('testA', 'testB'), ('testA', ''), ('testA', None), (None, None) ] for case in cases: print '-'.join(filter(bool, case)) 'testB' 'testB' 'testA-testB' 'testA' 'testA' for case in cases: print '-'.join([x for x in case if x]) 'testB' 'testB' 'testA-testB' 'testA' 'testA' </code></pre> <p>So let's do a benchmark :)</p> <pre><code>import timeit setup = ''' cases = [ (None, "testB"), ("", "testB"), ("testA","testB"), ("testA", ""), ("testA", None), (None, None) ] ''' print min(timeit.Timer( "for case in cases: '-'.join([x for x in case if x])", setup=setup ).repeat(5, 1000)) 0.00171494483948 print min(timeit.Timer( "for case in cases: '-'.join(filter(bool, case))", setup=setup ).repeat(5, 1000)) 0.00283288955688 </code></pre> <p>But, as @mgilson said, using <code>None</code> instead of <code>bool</code> as the function in <code>filter</code> produces the same result and have a quite better performance:</p> <pre><code>print min(timeit.Timer( "for case in cases: '-'.join(filter(None, case))", setup=setup ).repeat(5, 1000)) 0.00154685974121 </code></pre> <p>So, the best result is the answer gave by @icecrime with the suggestion from @mgilson:</p> <pre><code>'-'.join(filter(None, (a,b))) </code></pre> <p>The performance difference is in milliseconds per 1000 iterations (microseconds per iteration). So these two methods have a quite equals performance, and, for almost any project you could choose any one; In case your project must have a better performance, considering microseconds, you could follow this benchmark :)</p>
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    1. POWhat better way to concatenate string in python?
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    1. USRafael Verger
    1. USRafael Verger
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    1. COIs there something I'm missing. I've tried to copy and paste your code and it errors everytime
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    2. COAlso when I run my own time test, my way is slightly faster.
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    3. CO@Hoopdady, thanks! Something goes wrong with identations in `setup` declaration and I've missed a `)` in your code, fixed now!
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