1. 操作符

• 24.8.28 10:17 created

1.1. and

a = True
b = False
print(a and b)  # False

1.2. or

a = True
b = False
print(a or b)  # True

1.3. not

a = True
print(not a)  # False

1.4. operator - &

a = 60  # 0000 1100
b = 13  # 0000 1101
print(a & b) # 12 0000 1100

1.5. operator - |

a = 60  # 0000 1100
b = 13  # 0000 1101
print(a | b) # 61 0000 1101

1.6. operator - ^

a = 60  # 0000 1100
b = 13  # 0000 1101
print(a ^ b)  # 49 0011 0001

1.7. operator - ~

a = 60  # 0000 1100
print(~a)  # -61

1.8. operator - <<

a = 60  # 0000 1100
print(a << 2)  # 240 1111 0000

1.9. operator - >>

a = 60  # 0000 1100
print(a >> 2)  # 15 0000 1111

1.10. Truthy and Falsy Values

以下Collections、Sequences是假的（Falsy）：

• Empty lists []
• Empty tuples []
• Empty dictionaries {}
• Empty sets set()
• Empty strings ""
• Empty ranges range(0)

以下numbers是假的：

• Integer: 0
• Float: 0.0
• Complex: 0j

以下constant是假的：

• None
• False

真的值：

• 不为空的Collections、Sequences
• 不为0的数字
• True

# case 1
print(3 and 1)  # True
# case 2
if 3:
    print(True)
if []:
    print("empty list is true in boolean context")
else:
    print("empty list is false in boolean context")  # 走这里
print(bool(""))  # False
print(bool("Wilson"))  # True

1.11. short circuit

• 例如：如果 a and b，a为False，那么不需要检查b，这个表达式就是False
• 例如：如果 a or b， a为True，那么也不需要检查b，这个表达式就是True

# case 1
print([] and [])  # []
# case 2
if 2 or (10 / 0):
    print("we got no error")