Python之第十九天的努力--复习1

Posted 2020-12-12 szheng

复习

1. # str
   # upper   lower
   # startswith    endswith
   # s = ‘Python世界‘
   # print(s.upper())
   # print(s.lower())
   # print(s.startswith(‘P‘))
   # print(s.endswith(‘界‘))
   
   
   # replace
   # msg = ‘zs 很厉害，zs王者打的很好‘
   # msg1 = msg.replace(‘zs‘,‘ls‘)
   # msg2 = msg.replace(‘zs‘,‘ls‘,1)
   # print(msg1)
   # print(msg2)
   
   
   # strip
   # s = ‘ 	弟弟
   ‘
   # print(s.strip())
   
   # s = ‘qqw弟弟asd‘
   # print(s.strip(‘asdqw‘))
   
   
   # split
   # s = ‘zs ls ww‘
   # s1 = s.split()
   # print(s1)
   
   # s = ‘zs:ls:ww‘
   # s2 = s.split(‘:‘)
   # print(s2)
   
   # s2 = ‘:zs:ls:ww‘
   # s3 = s2.split(‘:‘)
   # s4 = s2.split(‘:‘,2)
   # print(s3)
   # print(s4)
   
   
   # join
   # s = ‘zs‘
   # s1 = ‘+‘.join(s)
   # print(s1)
   
   # s = [‘zs‘,‘ls‘,‘ww‘]
   # s1 = ‘:‘.join(s)
   # print(s1)
   
   
   # format
   # 格式化输出
   
   
   # is系列
   # name = ‘hcy123‘
   # print(name.isalnum())
   # print(name.isalpha())
   # print(name.isdecimal())
   
   
   
   
   # list
   # 增
   # l1 = [‘zs‘, ‘ls‘, ‘ww‘, ‘zl‘, ‘kk‘ ]
   # append    追加
   # l1.append(‘dd‘)
   # print(l1)
   
   # insert
   # l1.insert(1,‘dd‘)
   # print(l1)
   
   # extend
   # l1.extend(‘abcd‘)
   # print(l1)
   
   
   # 删
   # l1 = [‘zs‘, ‘ls‘, ‘ww‘, ‘zl‘, ‘kk‘ ]
   # pop
   # l1.pop(2)
   # print(l1)
   
   # remove    删头一个
   # l1.remove(‘ww‘)
   # print(l1)
   
   # clear
   # l1.clear()
   # print(l1)
   
   # del
   # del l1[-1]
   # print(l1)
   # del l1[::2]
   # print(l1)
   
   
   # 改
   # 索引切片
   
   
   # 查
   # 索引切片
   
   
   
   
   # tuple
   # 元组的拆包
   # a,b = (1,2)
   # print(a,b)
   
   
   
   # range
   
   
   
   
   # dict
   # 增
   # dic = {‘name‘:‘zs‘,‘age‘:18}
   # dic[‘sex‘] = ‘男‘
   # print(dic)
   # 有则改之  无则加之
   
   # setdefault
   # dic = {‘name‘:‘zs‘,‘age‘:18}
   # dic.setdefault(‘sex‘,‘男‘)
   # print(dic)
   # 有则不变  无则加之
   
   
   # 删
   # pop
   # dic = {‘name‘:‘zs‘,‘age‘:18}
   # dic.pop(‘age‘)
   # print(dic)
   
   
   # 改
   # 正常改
   
   
   # 查
   # get
   # dic = {‘name‘:‘zs‘,‘age‘:18}
   # l1 = dic.get(‘age‘)
   # l2 = dic.get(‘sex‘,‘无‘)
   # print(l1)
   # print(l2)
   
   
   # keys()
   # dic = {‘name‘:‘zs‘,‘age‘:18}
   # print(list(dic.keys()))
   
   # values()
   # dic = {‘name‘:‘zs‘,‘age‘:18}
   # print(list(dic.values()))
   
   # items()
   # dic = {‘name‘:‘zs‘,‘age‘:18}
   # print(dic.items())
   # for a,b in dic.items():
   #     print(a,b)
   

2. id == is

   id:返回地址

   ==:比较是否相等

   is:比较地址是否一样

3. 代码块

   • 一个文件就是一个代码块
   • 交互式界面一行就是一个代码块

4. 两个机制

   • 统一代码块下的缓存机制
     • 所有的数字，bool，几乎所有的字符串
     • 提升性能，节省内存
   • 不同代码块下的缓存机制：小数据池
     • -5~256数字，bool，一定规则的字符串
     • 提升性能，节省内存

5. 集合

   # 集合  无序
   # set
   # 空集合   set()
   
   # 增
   # set1 = {‘zs‘, ‘ls‘, ‘ww‘, ‘zl‘, ‘kk‘, ‘tt‘}
   # add
   # set1.add(‘dd‘)
   # print(set1)
   
   # updata 迭代着增
   # set1.update(‘abcd‘)
   # print(set1)
   
   
   # 删
   # set1 = {‘zs‘, ‘ls‘, ‘ww‘, ‘zl‘, ‘kk‘, ‘tt‘}
   # remove
   # set1.remove(‘ww‘)
   # print(set1)
   
   # pop   随机删除
   # set1.pop()
   # print(set1)
   
   
   # 用于列表去重
   # li = [1, 1, 2, ‘hhh‘, 2, 2, ‘hhh‘, 3, 4, 5, 6, ‘hhh‘, 6, 6]
   # set1 = set(li)
   # l1 = list(set1)
   # print(l1)
   

6. 深浅copy

   • 浅copy：copy一个外壳，里面值的地址不变。
   • 深copy：只有不可变类型数据不变。