布尔'和'在Python [英] boolean 'and' in Python

问题描述

有人能解释一下下面的测试??背后的原因

 ＆GT;＆GT;＆GT; 1和True
真正
＆GT;＆GT;＆GT; {'富'：'富'}和True
真正
＆GT;＆GT;＆GT; {}和True
{}
＆GT;＆GT;＆GT;
 

解决方案

在布尔运算的上下文，还当前pressions通过控制流语句中，以下值PTED为假间$ P $ ：虚假，无，所有类型的数字零，空字符串和容器（包括字符串，元组，列表，字典，集和frozensets）。所有其他值都PTED为真际$ P $。

这位前pression x和y首先计算X;如果x是假的，其值被返回;否则，y求值并返回结果值。

这位前pression x或y首先计算X;如果x为真，其值被返回;否则，y求值并返回结果值。

有关进一步的参考阅读更多的布尔操作：的http：/ /docs.python.org/reference/ex$p$pssions.html#boolean-operations

Can somebody explain the reasoning behind the following tests ??

>>> 1 and True
True
>>> {'foo': 'Foo'} and True
True
>>> {} and True
{}
>>>

解决方案

In the context of Boolean operations, and also when expressions are used by control flow statements, the following values are interpreted as false: False, None, numeric zero of all types, and empty strings and containers (including strings, tuples, lists, dictionaries, sets and frozensets). All other values are interpreted as true.

The expression x and y first evaluates x; if x is false, its value is returned; otherwise, y is evaluated and the resulting value is returned.

The expression x or y first evaluates x; if x is true, its value is returned; otherwise, y is evaluated and the resulting value is returned.

For further reference read more on Boolean operations: http://docs.python.org/reference/expressions.html#boolean-operations

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