如何检查一个str（变量）是否为空？ [英] How to check whether a str(variable) is empty or not?

问题描述

我如何制作：

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

条件？

（或某些原因，因为我敢肯定我刚才写的东西是完全错误的）

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

我是尝试检查列表中的 random.choice 是否为 [，] （空白）或包含 [ text，] 。

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

推荐答案

您可以比较一下字符串转换为空字符串：

You could just compare your string to the empty string:

if variable != "":
    etc.

但是您可以将其缩写为：

But you can abbreviate that as follows:

if variable:
    etc.

说明：An 如果实际上是通过为您提供的逻辑表达式计算值来工作的： True 或 False 。如果仅使用变量名（或诸如 hello之类的文字字符串）代替逻辑测试，则规则是：空字符串计为False，所有其他字符串计为True。空列表和数字零也算作假，其他大多数情况也算作真。

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.

这篇关于如何检查一个str（变量）是否为空？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！