Short-circuit evaluation like Python's "and" while storing results of checks
<p>I have multiple expensive functions that return results.  I want to return a tuple of the results of all the checks if all the checks succeed.  However, if one check fails I don't want to call the later checks, like the short-circuiting behavior of <code>and</code>.  I could nest <code>if</code> statements, but that will get out of hand if there are a lot of checks.  How can I get the short-circuit behavior of <code>and</code> while also storing the results for later use?</p>

<pre><code>def check_a():
    # do something and return the result,
    # for simplicity, just make it "A"
    return "A"

def check_b():
    # do something and return the result,
    # for simplicity, just make it "B"
    return "B"

...
</code></pre>

<p>This doesn't short-circuit:</p>

<pre><code>a = check_a()
b = check_b()
c = check_c()

if a and b and c:
    return a, b, c
</code></pre>

<p>This is messy if there are many checks:</p>

<pre><code>if a:
   b = check_b()

   if b:
      c = check_c()

      if c:
          return a, b, c
</code></pre>

<p>Is there a shorter way to do this?</p>

<p>If i understand correctly you don't need skip the last functions because if the the first condition fails, the others will not be evaluated. </p>

<p>For me your code:</p>

<pre><code>a = check_a()
b = check_b()
c = check_c()
....
if a and b and c and ...
    return (a, b, c, ...)
</code></pre>

<p>is right. If a fails, b and c will not be evaluated (redundant but necessary).</p>

python short-circuiting