知识点总结

Posted 2020-12-02 breaki

# python2
# print() print "abc"
# range() xrange()生成器
# raw_input()

# python3
# print("abc")
# range()
# input()

# = 赋值 == 比较值是否相等 is 比较内存是否相等 id(内容)
# li1 = [1, 2, 3]
# li2 = li1
# li2.append(‘4‘)
# print(li1)  # [1, 2, 3, ‘4‘]
# print(id(li2), id(li1))  # 2351029514056 2351029514056

# 数字 字符串 小数据池
# 数字的范围 -5 - 256（用的同一个id）
# 字符串：1.不能有特殊字符
#         2.s * 20 还是同一个地址 s * 21以后都是两个地址
# l1 = 6
# l2 = 6
# print(id(l1), id(l2))  # 1628859584 1628859584
#
# l3 = 300
# l4 = 300
# print(id(l3), id(l4))  # 2269162868528 2269163121520

# s1 = "s" * 20
# s2 = "s" * 20
# print(s1 is s2)  # True
#
# s1 = "s" * 21
# s2 = "s" * 21
# print(s1 is s2)  # False
#
# s1 = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaas"
# s2 = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaas"
# print(s1 is s2)
#
# s1 = "[email protected]"
# s2 = "[email protected]"
# print(s1 is s2)

# 除了数字和字符串其他的都没有小数据池


# 表现形式是将str转换成bytes类型
# 实际上是将unicode转换成utf-8 或者gbk
s1 = "Break"
# encode 编码，如何将str -》 bytes
s11 = s1.encode("utf-8")
print(s11) # b‘Break‘

s2 = "中国"
s22 = s2.encode("utf-8")
s222 = s2.encode("gbk")
print(s22) # b‘xe4xb8xadxe5x9bxbd‘
print(s222) # b‘xd6xd0xb9xfa‘