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PO"or" doesn't appear to function as it should in Python
 

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  1. PO"or" doesn't appear to function as it should in Python
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    <p>I'm trying to learn Python, and I've stumbled across this incredibly strange anomality whilst programming a "quiz" for my own learning purposes. The boolean "or" function is acting a little weird. Here's a piece of the code:</p> <pre><code>def answercheck(answer): solved = 0 while solved == 0: useranswer = raw_input("&gt; ") if useranswer == answer: solved = 1 correct() elif useranswer == "A" or "B" or "C" or "D": solved = 1 incorrect() else: print "False input. Try again." </code></pre> <p>Here's what happens. The answercheck function is called with the real answer as argument after a quiz question is printed out for the quiz contestant. The user is then prompted for an answer. Because I want the only valid answers to be "A", "B", "C" or "D", I've put the thing in a "while" loop.</p> <p>So, I would suspect, if someone made 'useranswer' something useless like 'lol' through raw_input, it would prompt the user again until "A", "B", "C" or "D" is inserted as answer. It doesn't, however, and takes any answer that isn't 'answer' as incorrect.</p> <p>So I rewrote the thing a little, and it appears to work when I do this:</p> <pre><code>def answercheck(answer): solved = 0 while solved == 0: useranswer = raw_input("&gt; ") if useranswer == answer: solved = 1 correct() elif useranswer == "A": solved = 1 incorrect() elif useranswer == "B": solved = 1 incorrect() elif useranswer == "C": solved = 1 incorrect() elif useranswer == "D": solved = 1 incorrect() else: print "False input. Try again." </code></pre> <p>This seems a little redundant to me. What is going wrong in the first script?</p>
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    1. USRuben Bakker
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    1. CO`or` is an expression, not a function..
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      1. USMartijn Pieters
    2. COThat isn't how `or` works - `or` takes the left hand side and the right hand side, and returns `True` if either side evaluates to `True`. What you have written makes sense in English, but not Python.
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      1. USGareth Latty
    3. CO_or_ is not a traditional boolean operator. It evaluates to the first item where bool(item)==True. So _'fred' or 'jane'_ is 'fred' and _None or 'jane'_ is 'jane'. With variables, _x=None; y='jane'; print x or y_ prints 'jane'.
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