在Python中使用AND和NOT运算符 [英] Using the AND and NOT Operator in Python

问题描述

这是我自定义的类，它代表一个三角形.我正在尝试编写代码以检查self.a，self.b和self.c是否大于0，这意味着我具有Angle，Angle和Angle.

Here is my custom class that I have that represents a triangle. I'm trying to write code that checks to see if self.a, self.b, and self.c are greater than 0, which would mean that I have Angle, Angle, Angle.

在下面，您将看到检查A和B的代码，但是当我只使用self.a != 0时，它可以正常工作.我相信我没有正确使用&.有任何想法吗?这是我的称呼方式:print myTri.detType()

Below you will see the code that checks for A and B, however when I use just self.a != 0 then it works fine. I believe I'm not using & correctly. Any ideas? Here is how I am calling it: print myTri.detType()

class Triangle:

    # Angle A To Angle C Connects Side F
    # Angle C to Angle B Connects Side D
    # Angle B to Angle A Connects Side E

    def __init__(self, a, b, c, d, e, f):
        self.a = a
        self.b = b
        self.c = c
        self.d = d
        self.e = e
        self.f = f

    def detType(self):
        #Triangle Type AAA
        if self.a != 0 & self.b != 0:
            return self.a

        #If self.a > 10:
            #return AAA

        #Triangle Type AAS

        #elif self.a = 0:
            #return AAS

        #Triangle Type ASA

        #Triangle Type SAS

        #Triangle Type SSS  

        #else:
            #return unknown

推荐答案

您应该写:

if (self.a != 0) and (self.b != 0) :

"&"是按位运算符，不适合布尔运算.在Python中，"&&"的等效项是和".

"&" is the bit wise operator and does not suit for boolean operations. The equivalent of "&&" is "and" in Python.

检查所需内容的一种较短方法是使用"in"运算符:

A shorter way to check what you want is to use the "in" operator :

if 0 not in (self.a, self.b) :

您可以使用"in"检查是否有任何内容是可迭代项的一部分，它适用于:

You can check if anything is part of a an iterable with "in", it works for :

• 组合.即:"foo" in ("foo", 1, c, etc)将返回true
• 列表.即:"foo" in ["foo", 1, c, etc]将返回true
• 字符串.即:"a" in "ago"将返回true
• 词典.即:"foo" in {"foo" : "bar"}将返回true

• Tuples. I.E : "foo" in ("foo", 1, c, etc) will return true
• Lists. I.E : "foo" in ["foo", 1, c, etc] will return true
• Strings. I.E : "a" in "ago" will return true
• Dict. I.E : "foo" in {"foo" : "bar"} will return true

作为评论的答案:

是的，由于要创建Tuple对象，因此使用"in"的速度较慢，但​​是实际上性能不是问题，在Python中可读性也很重要.

Yes, using "in" is slower since you are creating an Tuple object, but really performances are not an issue here, plus readability matters a lot in Python.

对于三角形检查，更容易阅读:

For the triangle check, it's easier to read :

0 not in (self.a, self.b, self.c)

比

(self.a != 0) and (self.b != 0) and (self.c != 0) 

重构也更容易.

当然，在此示例中，它并不是那么重要，它是非常简单的代码段.但是，这种风格导致了Python式代码的出现，从而导致大型程序上的程序员更加快乐(减轻体重，改善性生活等).

Of course, in this example, it really is not that important, it's very simple snippet. But this style leads to a Pythonic code, which leads to a happier programmer (and losing weight, improving sex life, etc.) on big programs.

这篇关于在Python中使用AND和NOT运算符的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！