小数据池：
int -5~256
str 特殊字符，*数字20
ascii : 8位 1字节 表示1个字符
unicode 32位 4个字节 表示一个字符
utf- 8 1个英文 8位，1个字节
欧洲 16位 两个字节 表示一个字符
亚洲 24位 三个字节 表示一个字符
gbk 1个英文 8位，1个字节
亚洲 16位 两个字节 表示一个字符
s = 'alex'
b = s.encode('utf-8')
print(b) # b'alex'
1,基础数据类型汇总补充
str
int
list
在循环一个列表时，最好不要删除列表中的元素，这样会使索引发生改变，从而报错。
bool
dict
1,fromkeys()
tuple
2，集合set
3，深浅copy
''' str int ''' # str # # s = '' # # print(s.isspace()) # int ''' list: ''' lis = [11,22,33,44,55] # for i in range(len(lis)): # print(i) # i = 0 i = 1 i = 2 # del lis[i] # print(lis) # [11,22,33,44,55] [22, 44, 55] [22, 44] #第一种 # lis = lis[::2] # print(lis) #第二种 # l1 = [] # for i in lis: # if lis.index(i) % 2 == 0: # l1.append(i) # lis = l1 # print(lis) # lis = [11,22,33,44,55] # # for i in range(len(lis)-1,-1,-1): # # if i % 2 == 1: # # print(i) # # del lis[i] # # print(lis) # # print(lis) # dic = dict.fromkeys([1,2,3],'春哥') # print(dic) # dic = dict.fromkeys([1,2,3],[]) # print(dic) # {1: [], 2: [], 3: []} # dic[1].append('袁姐') # print(dic) # dic[2].extend('二哥') # print(dic) # l1 = [] # l2 = l1 # l3 = l1 # l3.append('a') # print(l1,l2,l3) # dic = {'k1':'v1','k2':'v2','a3':'v3'} # dic1 = {} # # for i in dic: # if 'k' not in i: # dic1.setdefault(i,dic[i]) # dic = dic1 # print(dic) # l = [] # for i in dic: # if 'k' in i: # l.append(i) # for i in l: # del dic[i] # print(dic) # 转化成bool值 # 0 '' [] () {} set() #元祖 如果元祖里面只有一个元素且不加,那此元素是什么类型，就是什么类型。 # tu1 = (1) # tu2 = (1,) # print(tu1,type(tu1)) # print(tu2,type(tu2)) # tu1 = ([1]) # tu2 = ([1],) # print(tu1,type(tu1)) # print(tu2,type(tu2)) # dic = dict.fromkeys([1,2,3,],3) # dic[1] = 4 # print(dic)
# 赋值运算 # l1 = [1,2,3] # l2 = l1 # l1.append('a') # print(l1,l2) #copy # l1 = [1,2,3] # l2 = l1.copy() # print(l1,l2) # print(id(l1),id(l2)) # l2.append('a') # print(l1,l2) # l1 = [1,2,[4,5,6],3] # l2 = l1.copy() # print(l1,id(l1)) # print(l2,id(l2)) # l1.append('a') # print(l1,l2) # l1[2].append('a') # print(l1,l2) # print(id(l1[2])) # print(id(l2[2])) import copy # l1 = [1,2,[4,5,6],3] # l2 = copy.deepcopy(l1) # print(l1,id(l1)) # print(l2,id(l2)) # l1[2].append('a') # print(l1,l2) # l1 = [1,[1],2,3,4] # l2 = l1[:] # l1[1].append('a') #l2 的结果是什么? # print(l1,id(l1)) # print(l2,id(l2)) # print(l1[1] is l2[1]) # li = ['alex','taibai','wusir','egon'] # for i in li: # print(li.index(i),i) # for index,i in enumerate(li,1): # print(index,i)
''' 集合：可变的数据类型，他里面的元素必须是不可变的数据类型，无序，不重复。 {} ''' # set1 = set({1,2,3}) # set2 = {1,2,3,[2,3],{'name':'alex'}} # 错的 # print(set1) # print(set2) # set1 = {'alex','wusir','ritian','egon','barry',} #增 #add # set1.add('女神') # print(set1) #update # set1.update('abc') # print(set1) #删除 # set1.pop() # 随机删除 # print(set1.pop()) # 有返回值 # print(set1) # set1.remove('alex') # 按元素 # print(set1) #{} set() # set1.clear() # print(set1) # set() # del set1 # print(set1) #查 # for i in set1: # print(i) # set1 = {1,2,3,4,5} # set2 = {4,5,6,7,8} # set3 = set1 & set2 # print(set3) # {4, 5} # print(set1.intersection(set2)) # {4, 5} # set1 = {1,2,3,4,5} # set2 = {4,5,6,7,8} # print(set1 | set2) # {1, 2, 3, 4, 5, 6, 7,8} # print(set2.union(set1)) # {1, 2, 3, 4, 5, 6, 7} # set1 = {1,2,3,4,5} # set2 = {4,5,6,7,8} # print(set1 ^ set2) # {1, 2, 3, 6, 7, 8} # print(set1.symmetric_difference(set2)) # {1, 2, 3, 6, 7, 8} # set1 = {1,2,3,4,5} # set2 = {4,5,6,7,8} # print(set1 - set2) # {1, 2, 3} # #set1独有的 # print(set1.difference(set2)) # {1, 2, 3} # set1 = {1,2,3,} # set2 = {1,2,3,4,5,6} # # print(set1 < set2) # print(set1.issubset(set2)) # 这两个相同，都是说明set1是set2子集。 # print(set2 > set1) # print(set2.issuperset(set1)) # 这两个相同，都是说明set2是set1超集。 #去重 # li = [1,2,33,33,2,1,4,5,6,6] # set1 = set(li) # # print(set1) # li = list(set1) # print(li) # s1 = {1,2,3} # print(s1,type(s1)) # s = frozenset('barry') # print(s,type(s)) # for i in s: # print(i)