如果不同变量为真或假python3.3，则打印

Question

在检查变量是否为真或假后，我无法打印消息。我要做的是打印出一系列变量中为真的变量。一定有比下面更简单的方法，但这是我能想到的。我需要一个更好的解决方案或修改下面的工作。在

这是我的代码：

if (quirk) and not (minor, creator, nature):
    print (quirk, item)
elif (minor) and not (quirk, creator, nature):
    print (minor, item)
elif (creator) and not (minor, quirk, nature):
    print (creator, item)
elif (nature) and not (minor, quirk, creator):
    print (item, nature)
else:
    print ("Something went wrong! Properties out of range! Nature =",nature,"Quirk =",quirk,"Minor =",minor,"Creator =",creator)

在这种情况下，我总是得到错误，从来没有任何指纹。错误总是显示其中一个变量是真的。在

提前谢谢你！在

Answer 1

你正在检查一个非空元组是否是falsish-这永远不是真的。请改用^{}。在

if quirk and not any([minor, creator, nature]):
    print (quirk, item)
# and so on

any([minor, creator, nature])如果集合中有任何元素是True，则返回{}，否则返回{}。在

Answer 2

(minor, creator, nature)

是元组。它总是在布尔上下文中求值为True，而不管minor、creator和{}的值。在

这是documentation for Truth Value Testing要说的：

Any object can be tested for truth value, for use in an if or while condition or as operand of the Boolean operations below. The following values are considered false:

• None
• False
• zero of any numeric type, for example, 0, 0.0, 0j.
• any empty sequence, for example, '', (), [].
• any empty mapping, for example, {}.
• instances of user-defined classes, if the class defines a bool() or len() method, when that method returns the integer zero or bool value False.

All other values are considered true — so objects of many types are always true.

您的非空序列属于“所有其他值”类别，因此被认为是真的。在

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要使用纯Python逻辑表示条件，需要编写：

^{pr2}$

正如@volatile指出的，any()实用函数可以用来简化代码并使其读得更清楚。在

Answer 3

any在这里感觉太过分了：

if quirk and not (minor or creator or nature):
    print (quirk, item)
elif minor and not (quirk or creator or nature):
    print (minor, item)
elif creator and not (minor or quirk or nature):
    print (creator, item)
elif nature and not (minor or quirk or creator):
    print (item, nature)
else:
    print ("Something went wrong! Properties out of range! Nature =",nature,"Quirk =",quirk,"Minor =",minor,"Creator =",creator)