如何在“如果”条件布尔运算符的工作？ [英] How do boolean operators work in 'if' conditions?

问题描述

我目前新的Python，我试图运行code的几行简单​​。我不明白的Python是如何评估的如果的语句之后此语法。任何解释将AP preciated。

I am currently new to Python and am trying to run a few simple lines of code. I cannot understand how Python is evaluating this syntax after the if statement. Any explanations will be appreciated.

number = int(raw_input("Enter number : "))

if number == (1 or 2 or 3):
    print "Match"
else:
    print "No match"

只有整数1屈服一个积极的结果和其他任何数字，包括2,3经过的其他的分支。条件可以表述为如下唯一：

Only the integer 1 yield a positive result and any other numbers including 2 and 3 go through the else branch. Can the conditions be stated as the following only?:

if number == 1 or number == 2 or number == 3:

感谢您。

推荐答案

Python有布尔值，如真和假 并且它还具有的 falsy 值，如任何空列表，元组，或者字典，一个空字符串， 0 和无。 Truthy值是是相反的，也就是被定义的东西。

Python has boolean values, such as True and False, and it also has falsy values, such as any empty list, tuple, or dictionary, an empty string, 0, and None. Truthy values are the opposite of that, namely anything that's defined.

Python中的或的评估和短circuts在第一元素，它返回一个值truthy 的上

Python's or evaluates and short-circuts on the first element that returns a truthy value.

所以，前pression （1或2或3）是要返回 1 。

So, the expression (1 or 2 or 3) is going to return 1.

如果您想比较的所有的元素，那么你在关键字寻找：

If you want to compare against all elements, then you're looking for the in keyword:

if number in (1, 2, 3):
    # Do logic

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