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  • day8数据类型补充,集合,深浅拷贝

    思维导图:

    集合的补充:下面的思维导图有一个点搞错了,在这里纠正一下,没有合集,是反交集,^这个是反差集的意思 。

      交集&,反交集^,差集-,并集|,然后就是子集和超集

    数据类型补充:

      1 '''
      2 1,int
      3 2,str
      4 3,tuple
      5     tu = (1)
      6     tu1 = ('name',)
      7     print(tu,type(tu))  # 1 <class 'int'>
      8     print(tu1,type(tu1))
      9     
     10     tu = ('dfas')
     11     tu1 = ('name',)
     12     print(tu,type(tu))  # dfas <class 'str'>
     13     print(tu1,type(tu1))
     14     
     15     tu = (True)
     16     tu1 = ('name',)
     17     print(tu,type(tu))  # True <class 'bool'>
     18     print(tu1,type(tu1))
     19     
     20     tu = ([1,2,3])
     21     tu1 = ('name',)
     22     print(tu,type(tu))  # [1, 2, 3] <class 'list'>
     23     print(tu1,type(tu1))
     24 4,列表
     25 当循环列表时,如果在循环中删除某个或者某些元素,列表元素个数改变,索引改变,容易出错。
     26 
     27 5,字典
     28 当循环字典时,如果在循环中删除某个或者某些键值对,字典的键值对个数改变,长度改变,容易出错。
     29 
     30 转化:
     31 1,int --> str :str(int)
     32 2, str ---> int:int(str) 字符串必须全部由数字组成
     33 3,bool ---> str:str(bool)
     34 4,str ----> bool(str)    除了空字符串,剩下的都是True
     35 5,int ---> bool  除了0,剩下的全是True
     36 6,bool ---> int  True ---> 1 False ----> 0
     37 7,str ---> list  split
     38 8,list ---> str() join
     39 9,元祖列表:
     40 tu = (1,2,3)
     41 l = list(tu)
     42 print(l,type(l))
     43 
     44 li = [4,5,6]
     45 print(tuple(li),type(tuple(li)))
     46 
     47 #str ---> list
     48 print(list('ab_c'))
     49 
     50 #str ---> list
     51 print(tuple('ab_c'))
     52 
     53 # 0,"",{},[],(),set()   ---->False
     54 
     55 
     56 
     57 
     58 '''
     59 '''
     60 # li = [11,22,33,44,55]
     61 # for i in range(0,len(li)):
     62 #     #  i = 0             i= 1        i = 2      i = 3
     63 #     del li[li]
     64     #li[22,33,44,55]   li [22,44,55]  li [22,44]
     65 
     66 # for i in li:
     67 #     if li.index(i) % 2 == 1:  # i = 11                i = 22              i = 44
     68 #         del li[li.index(i)]    # li [11,22,33,44,55]  li = [11,33,44,55]   [11,33,44,55]
     69 # print(li)  # [11, 33, 44]
     70 li = [11,22,33,44,55]
     71 # 方法一
     72 # l2 = []
     73 # for i in range(0,len(li)):
     74 #     if i % 2 == 0:
     75 #         l2.append(li[i])
     76 # li = l2
     77 # print(li)
     78 #方法二
     79 # del li[1::2]
     80 # print(li)
     81 # li = li[0::2]
     82 # print(li)
     83 
     84 #方法三
     85 # li = [11,22,33,44,55]
     86 # for i in range(0,len(li)//2):
     87 #     # i = 0                   #  i = 1
     88 #     del li[i+1]
     89 #     # li = [11,33,44,55]      li = [11,33,55]
     90 # print(li)
     91 
     92 # li = [11,22,33,44,55]
     93 # # for i in range(len(li)-1,0,-1):
     94 # #     print(i)
     95 # for i in range(len(li)-1,0,-1):
     96 #     if i % 2 == 1:
     97 #         del li[i]
     98 # print(li)
     99 '''
    100 # dic = dict.fromkeys([1,2,3],'杨杰')
    101 # # dic1 = dict.fromkeys('abc','杨杰')
    102 # print(dic)
    103 # dic[4] = 'dfdsa'
    104 
    105 # print(dic1)
    106 # dic = dict.fromkeys(['barry','alex',],[])
    107 # dic['ritian'] = []
    108 # dic['barry'] = []
    109 # dic['barry'].append(11)
    110 # print(dic)
    111 
    112 
    113 dic = {'k1':'barry','k2':'alex','name':'ritian'}
    114 '''
    115 # for i in dic:
    116 #     if 'k' in i:
    117 #         del dic[i]
    118 # a = dic.keys()
    119 # for i in list(a):
    120 #     if 'k' in i:
    121 #         del dic[i]
    122 # print(dic)
    123 '''
    124 # for i in dic:
    125 #     if 'k' in i:
    126 #         del dic[i]
    127 # print(dic)
    128 # for key in dic:
    129 #     print(key)
    130 # li = []
    131 # for key in dic:
    132 #     li.append(key)
    133 # print(li)
    134 # for i in li:
    135 #     if 'k' in i:
    136 #         del dic[i]
    137 # print(dic)
    138 # lis = []
    139 # dic = {}
    140 # i = 1
    141 # dic["k1"] = i
    142 # print("此时字典为%s:"%dic)
    143 # lis.append(dic)
    144 # print("此时列表为%s:"%lis)
    145 # j = 2
    146 # dic["k1"] = j
    147 # print("此时字典为%s:"%dic)
    148 # lis.append(dic)
    149 # print("此时列表为%s:"%lis)
    150 
    151 # tu = (1,2,3)
    152 # l = list(tu)
    153 # print(l,type(l))
    154 #
    155 # li = [4,5,6]
    156 # print(tuple(li),type(tuple(li)))
    157 
    158 # #str ---> list
    159 # print(list('ab_c'))
    160 #
    161 # #str ---> list
    162 # print(tuple('ab_c'))
    163 
    164 # 0,"",{},[],(),set()   ---->False
    View Code

     今日内容梗概:

    1,上节内容回顾 2,数据类型补充 3,集合。 4,深浅拷贝。

    上节内容回顾:

    1,id() 内存地址 2, == 比较的是值     is  比较的是内存地址     数字,字符串,有小数据池,     int -5--256     str:1,不能有空格。          2,长度不能超过20。          3,不能有特殊字符如:#@.....

    3,enmurate枚举  iterable: str,list,tuple,dict,set for i in enmurate(iterable):     pirnt(i) for i in enmurate(['barry','alex']):     pirnt(i)  # (0,'barry') (1,'alex') for index,i in enmurate(['barry','alex']):     pirnt(index,i)  # 0,'barry'                       1,'alex' for index,i in enmurate(['barry','alex'],100):     pirnt(index,i)  # 100,'barry'                       101,'alex' 4,编码 py3:     str:表现形式:s = 'alex'  实际编码方式:unicode     bytes:表现形式:s = b'alex'  实际编码方式:utf-8,gbk,gb2312...                     s =  b'x2ex2ex2ex2ex2ex2e'     unicode:所有字符(无论英文,中文等) 1个字符:4个字节     gbk:一个字符,英文1个字节,中文两个字节。     utf-8:英文 1 个字节,欧洲:2个字节,亚洲:3个字节。

     集合:

     1 # set1 = {'1','alex',2,True,2,'alex'}
     2 # print(set1)
     3 #里面的元素是可哈希的
     4 # set1 = {'1','alex',2,True,[1,2,3]} # 报错
     5 # set2 = {'1','alex',2,True,{1:2}}  # 报错
     6 # set3 = {'1','alex',2,True,(1,2,[2,3,4])}  # 报错
     7 
     8 # l = [1,1,2,2,3,4,5,5]
     9 # set1 = set(l)
    10 # print(set1)
    11 # l = list(set1)
    12 # print(l)
    13 
    14 #创建:
    15 # set1 = {1,2,3}
    16 # set2 = set({1,2,'barry'})
    17 # print(set1,set2)
    18 
    19 #
    20 
    21 # set1 = {'alex','wusir','ritian','egon','barry'}
    22 # set1.add('景女神')
    23 # print(set1)
    24 
    25 # #update:迭代着增加
    26 # set1.update('A')
    27 # print(set1)
    28 # set1.update('老师')
    29 # print(set1)
    30 # set1.update([1,2,3])
    31 # print(set1)
    32 
    33 
    34 # set1 = {'alex','wusir','ritian','egon','barry'}
    35 
    36 # set1.remove('alex')  # 删除一个元素
    37 # print(set1)
    38 
    39 # s = set1.pop()  # 随机删除一个元素  有返回值
    40 # print(set1)
    41 # print(s)
    42 #
    43 # set1.clear()  # 清空集合
    44 # print(set1)
    45 #
    46 # del set1  # 删除集合
    47 # print(set1)
    48 
    49 # for i in set1:
    50 #     print(i)
    51 # tu = ()
    52 # print(tu,type(tu))
    53 
    54 #交集  &  intersection
    55 # set1 = {1,2,3,4,5}
    56 # set2 = {4,5,6,7,8}
    57 # print(set1 & set2)  # {4, 5}
    58 # print(set1.intersection(set2))  # {4, 5}
    59 
    60 # set1 = {1,2,3,4,5}
    61 # set2 = {4,5,6,7,8}
    62 # print(set1 | set2)  # {1, 2, 3, 4, 5, 6, 7}
    63 # print(set2.union(set1))  # {1, 2, 3, 4, 5, 6, 7}
    64 
    65 # set1 = {1,2,3,4,5}
    66 # set2 = {4,5,6,7,8}
    67 # print(set1 - set2)  # {1, 2, 3}  set1独有
    68 # print(set1.difference(set2))  # {1, 2, 3}
    69 # print(set2 - set1)
    70 
    71 # set1 = {1,2,3,4,5}
    72 # set2 = {4,5,6,7,8}
    73 # print(set1 ^ set2)  # {1, 2, 3, 6, 7, 8}
    74 # print(set1.symmetric_difference(set2))  # {1, 2, 3, 6, 7, 8}
    75 # set1 = {1,2,3}
    76 # set2 = {1,2,8,4,5,6}
    77 # print(set1 < set2)  # set1是set2的子集
    78 # print(set1.issubset(set2))  # set1是set2的子集
    79 # print(set2 > set1)  # set2 是set1 的超集
    80 # print(set2.issuperset(set1))  # 这两个相同,都是说明set2是set1超集。
    81 
    82 # s = frozenset([1,2,33,33,4])
    83 # print(s,type(s))
    View Code

     集合的补充:之前的思维导图有一个点搞错了,在这里纠正一下,没有合集,是反交集,^这个是反差集的意思 。

      交集&,反交集^,差集-,并集|,然后就是子集和超集

    copy深浅:

     1 # l1 = [1,2,3]
     2 # l2 = l1
     3 # l1.append('barry')
     4 # print(l1)  # [1,2,3,'barry']
     5 # print(l2)  # [1,2,3]
     6 
     7 # dic = {'name':'barry'}
     8 # dic1 = dic
     9 # dic['age'] = 18
    10 # print(dic)
    11 # print(dic1)
    12 
    13 # s = 'alex'
    14 # s1 = s
    15 # s3 = s.replace('e','E')
    16 # print(s)
    17 # print(s1)
    18 # print(s3)
    19 # s = 'alex'
    20 # s1 = s
    21 # print(id(s),id(s1))
    22 # s = 'alex '
    23 # s1 = 'alex '
    24 # print(id(s),id(s1))
    25 
    26 # 浅copy 以list举例
    27 # l1 = [1,2,3,4]
    28 # l2 = l1.copy()
    29 # l1.append('barry')
    30 # print(l1,id(l1))
    31 # print(l2,id(l2))
    32 
    33 # l1 = [1,[22,33,44],3,4,]
    34 # l2 = l1.copy()
    35 # l1[1].append('55')
    36 # # print(l1,id(l1),id(l1[1]))
    37 # # print(l2,id(l2),id(l2[1]))
    38 # l1[0] = 111
    39 # print(l1,l2)
    40 
    41 #深copy
    42 import copy
    43 l1 = [1,[22,33,44],3,4,]
    44 l2 = copy.deepcopy(l1)
    45 
    46 l1[0] = 111
    47 print(l1,l2)
    48 
    49 l1[1].append('barry')
    50 print(l1,l2)
    View Code
    #深浅copy的区别是,浅copy的列表嵌,
    从第一层开始,改变原本的,copy的那一份并不会变
    从第二层的列表开始,改变原本的,copy的那一份也会跟着改变;


    l = [1,2,3,[3,4]]
    l1 = l.copy()
    l[-1].append(8);
    l.append(89)

    print(l,l1)
    输出结果是:[1, 2, 3, [3, 4, 8],89] [1, 2, 3, [3, 4, 8]]
    #对于深copy来说,不论有几层的嵌套,随便改变里面的每一层,都不会影响原本的或者copy的那一份。
    import copy
    l = [1,2,3,[3,4]]
    l1 = copy.deepcopy(l)
    l[-1].append(8)
    print(l,l1)

    [1, 2, 3, [3, 4, 8]] [1, 2, 3, [3, 4]]

    
    
    l1 = [1, 2, 3, ['barry', 'alex']]

    # 浅copy
    l2 = l1.copy()
    # l1[3].append('b')
    # l1.insert(l1[0], 'abs')
    # print(l1, id(l1))
    # print(l2, id(l2))
    '''
    [1, 2, 3, ['barry', 'alex', 'b']] 4367967368
    [1, 2, 3, ['barry', 'alex', 'b']] 4367868680 l2是copy出来的,浅copy的时候,原来的内嵌列表改变,它也跟着变;
    '''
    '''
    [1, 'abs', 2, 3, ['barry', 'alex']] 4367963272
    [1, 2, 3, ['barry', 'alex']] 4367868680 原来的外层改变,它不变
    '''


    # 深copy
    l3 = copy.deepcopy(l1)
    l1[3].append('bpo')
    l1.append('bpo')

    # print(l3,id(l3))
    # print(l1,id(l1))

    '''
    [1, 2, 3, ['barry', 'alex']] 4368117640
    [1, 2, 3, ['barry', 'alex', 'bpo'], 'bpo'] 4367967368 # 对于深copy来说,不论改变原来的哪一层,copy出来的都不会随之改变
    '''
     

    周末计划安排:

    1,周六上午:整理知识点,+ 错题。 2,周六下午:小憩一下,做作业,看个电影。 3,周天上午:睡个懒觉,整理作业+预习。 4,周天下午:自由发挥。

    周六作业: # 30、购物车 # 功能要求:要求用户输入总资产,例如:2000显示商品列表, 让用户根据序号选择商品,加入购物车购买,如果商品总额大于总资产,提示账户余额不足, 否则,购买成功。 # goods=[{"name":"电脑","price":1999},         {"name":"鼠标","price":10},         {"name":"游艇","price":20},         {"name":"美女","price":998},         ]

    shopping_car = []

    1 input(钱) 序号,商品,钱 序号选择:判断条件 深一步,你的 input(钱) 与 price":1999比较

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  • 原文地址:https://www.cnblogs.com/2012-dream/p/7743395.html
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