如何检查 str(variable) 是否为空?

2022-01-20 00:00:00 python string conditional-statements

问题描述

如何制作:

if str(variable) == [contains text]:

条件?

(或者什么，因为我很确定我刚才写的完全错了)

(or something, because I am pretty sure that what I just wrote is completely wrong)

我正在尝试检查列表中的 random.choice 是 ["",](空白)还是包含 ["text",].

I am sort of trying to check if a random.choice from my list is ["",] (blank) or contains ["text",].

解决方案

你可以只比较你的字符串和空字符串:

You could just compare your string to the empty string:

if variable != "": etc.

但你可以缩写如下:

if variable: etc.

说明:if 实际上是通过计算您给它的逻辑表达式的值来工作的:True 或 False.如果您只是使用变量名(或hello"之类的文字字符串)而不是逻辑测试，则规则是:空字符串计为 False，所有其他字符串计为 True.空列表和数字 0 也算作假，而其他大多数情况都算作真.

Explanation: An if actually works by computing a value for the logical expression you give it: True or False. If you simply use a variable name (or a literal string like "hello") instead of a logical test, the rule is: An empty string counts as False, all other strings count as True. Empty lists and the number zero also count as false, and most other things count as true.

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