Python3中真真假假True、False、None等含义详解
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<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">概述</strong></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在Python中，<span style="color: black;">不仅</span>和类C<span style="color: black;">同样</span>的真假类似，<span style="color: black;">例如</span>1<span style="color: black;">表率</span>真，0<span style="color: black;">表率</span>假。Python中的真假有着更加广阔的含义范围，Python会把所有的空数据结构视为假，<span style="color: black;">例如</span>[](空列表)、{}（空集合）、（空字符串）等，而与之相反的非空数据结构即为真</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">简单对比代码：</strong></p># 遍历列表中的示例元素，获取对应的真假：
for elenment in [, S, [], , {}, {3, SSS}, 0, 0.0, 1, None]:
if elenment:
print(elenment, True)
else:
print(elenment, False)<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">示例结果：</strong></p>False
S True
[] False
True
{} False
{SSS, 3} True
0 False
0.0 False
1 True
None False<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">None对象</strong></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在Python中None<span style="color: black;">不仅</span><span style="color: black;">表率</span>False，它本身<span style="color: black;">便是</span>一个特殊的空对象，<span style="color: black;">能够</span>用来占位，<span style="color: black;">例如</span><span style="color: black;">咱们</span><span style="color: black;">能够</span>利用None实现类似C中定义数组的方式，预定义列表的<span style="color: black;">体积</span>，实现对可能的索引进行赋值，而为赋值的索引都为None</p>L = * 10
print(L)<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">空列表定义结果</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">布尔(bool)值</strong></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在Python中布尔值，True和False<span style="color: black;">不仅</span><span style="color: black;">能够</span><span style="color: black;">暗示</span>真与假，<span style="color: black;">乃至</span><span style="color: black;">能够</span>用于数学运算：</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">python print(True+1) print(False+1) print(True+False) ¨G4G 2 1 1 ¨G5G python print(isinstance(True, int)) print(isinstance(False, int)) ¨G6G True True</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">即实质上在Python中布尔值本身是整型(int)，即bool类型<span style="color: black;">便是</span>int类型的子类。</p>
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