什么是真和假?它与 True 和 False 有何不同? [英] What is Truthy and Falsy? How is it different from True and False?

问题描述

我刚刚了解到 python 中有 truthy 和 falsy 值，它们与正常的 True 和 False 不同>.

I just learned there are truthy and falsy values in python which are different from the normal True and False.

有人可以深入解释一下什么是true 和 falsy 值吗?我应该在哪里使用它们?truthy 和 True 值与 falsy 和 False 值之间有什么区别?

Can someone please explain in depth what truthy and falsy values are? Where should I use them? What is the difference between truthy and True values and falsy and False values?

推荐答案

正如评论所描述的，它只是指被评估为 True 或 False 的值.

As the comments described, it just refers to values which are evaluated to True or False.

例如，查看列表是否为空，而不是像这样检查:

For instance, to see if a list is not empty, instead of checking like this:

if len(my_list) != 0:
   print("Not empty!")

你可以简单地这样做:

if my_list:
   print("Not empty!")

这是因为某些值(例如空列表)在评估布尔值时被视为 False.非空列表为 True.

This is because some values, such as empty lists, are considered False when evaluated for a boolean value. Non-empty lists are True.

类似地，对于整数 0、空字符串 "" 等，对于 False，以及非零整数、非空字符串等，对于 True.

Similarly for the integer 0, the empty string "", and so on, for False, and non-zero integers, non-empty strings, and so on, for True.

truthy"和falsy"等术语的概念仅指在上述情况下被视为真的值，以及在上述情况下被视为假的值.

The idea of terms like "truthy" and "falsy" simply refer to those values which are considered True in cases like those described above, and those which are considered False.

例如，空列表([])被认为是falsy"，非空列表(例如，[1])被认为是真实".

For example, an empty list ([]) is considered "falsy", and a non-empty list (for example, [1]) is considered "truthy".

另请参阅文档的这一部分.

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