布尔类型已添加到 Python 2.3.添加了两个新常量到 builtin 模块，True 和 False.(真假常数已添加到 Python 2.2.1 的内置函数中，但 2.2.1 版本被简单地设置为 1 和 0 的整数值并且没有什么不同输入.)

A Boolean type was added to Python 2.3. Two new constants were added to the builtin module, True and False. (True and False constants were added to the built-ins in Python 2.2.1, but the 2.2.1 versions are simply set to integer values of 1 and 0 and aren't a different type.)

bool 是 int 的子类，有两个单例值，True 和 False，它们等于1 和 0 分别.Python 在内部进行这种转换.请参阅以下示例:

bool is a subclass of int with two singleton values, True and False, that are equal to 1 and 0 respectively. Python does this conversion internally. See the below samples:

print(True + 1)      # outputs 2
print(True - 1)      # outputs 0
print(True - 2)      # outputs -1
a = True
print(a)             # outputs True because no mathematical calculation
print(True + True + 1) # Outputs 3
print(False + 1)     #  Outputs 3
print(False + True)     #  Outputs 1

参考:

• https://docs.python.org/2.3/whatsnew/section-bool.html
• https://www.python.org/dev/peps/pep-0285/