# 字典 # dict # info = {"k1":"v1","k2":"v2","k3":True,"k4":[11,22,33],"k5":()} # 1可以嵌套,value 可以是任何值 # 2布尔值(0,1),列表、字典不能作为字典的key # info = { # 1:"asdf", # "k1":"adadf", # True:"123", # (11,22):345 # } # print(info) # 3字典是无序的。打印出来的时候顺序不一定。 # 取值的时候中括号中参数加上key即可。 # 通索引方式找到指定元素 # v = info["k3"][2]["sd"] # # 4删除字典中的某一个键值对 # del info["k1"] # del info["k3"][3] # print(info) # 5for循环,默认for循环只有key # for item in info: # print(item) # # 6加上参数可以获取value或者只有获取value # for item in info.values(): # print(item,info[item]) # for item in info.keys(): # print(item,info[item]) # -------------------------------- # for k,v in info.items(): # print(k,v) # 字典特有的相关操作: # # 1、根据序列来创建字典,并给统一的值 # fromkeys # dic = { # "k1":"v1" # } # v = dict.fromkeys(["k1",124,"888"],124) # print(v) # 2、取值: # dic.get("k1") # get 的方式如果key不存在时,系统不会报错,可以指定默认值,none # # # 3、删除并获取值 # dic.pop # dic.popitem() # # 4、设置值,如果已经存在就是获取当前key对应的值, # 如果不存在就进行添加设置。 # dic.setdefault("key","value") # # # 5、更新 # 如果存在即更新 # 如果不存在就添加 # dic.update # # dic.update(k1=124,k3=345,k5="adfadf")#或者在括号中用“:”来标识键值对 # # # 6、keys() # 7、values() # 8、items() get() update # # # ############整理############必须要会的 # 1、数字 # int(..) , # #2、 字符串 # replace/find/join/strip/startswith/split/upper/lower/format # tempalte = "i am {name},age:{age}" # v = tempalte.format(name="alex",age=19) # v = tempalte.format({**"name":"alex","age":19}) # print(v) 3、列表 append/extend/insert/ 索引、切片、循环 4、元组 索引、切片、循环 以及元素不能被修改 5、字典 get/update/keys/values/items for,索引,in 默认是查询key 6、布尔值 0 1 bool() None "" ,(), [],{},0 =>Fals ----------------------------------------------- 练习题
#!/usr/bin/env python # -*- coding:utf-8 -*- # l = [11,22,33,44,55,66,77,88,99,90] # result = {} # # {'k1': [77, 88, 99, 90], 'k2': [11, 22, 33, 44, 55]} # # for item in l: # if item < 66: # # result.update({"k1": item}) # {'k1':11} # # {'k1': [11,22]} # if "k1" not in result: # result['k1'] = [item, ] # {'k1': [11,]} # else: # result['k1'].append(item) # elif item > 66: # if "k2" not in result: # result['k2'] = [item, ] # {'k1': [11,]} # else: # result['k2'].append(item) # for i in l: # if i < 66: # a.append(i) # if i > 66: # b.append(i) # print({'k1':b,'k2':a}) # 有两个列表 # l1 = [11,22,33] # l2 = [22,33,44] # a. 获取内容相同的元素列表 # b. 获取 l1 中有, l2 中没有的元素列表 # c. 获取 l2 中有, l1 中没有的元素列表 # d. 获取 l1 和 l2 中内容都不同的元素 l1 = [11,22,33] l2 = [22,33,44] # for i in l2: # if i not in l1: # print(i) # for i in l2: # if i not in l1: # print(i) count =0 for i in range(1, 9): for v in range(1, 9): if i !=v: count += 1 # count = count -8 print(count) # # count =0 # ls = [3,5,8,9] # for i in range(0, len(ls)): # for v in range(0, len(ls)): # if i !=v: # count += 1 # # count = count -8 # print(count) #99乘法表 # for i in range(1,10): # string = "" # for j in range(1,i+1): # string +=str(j) + " * "+str(i) + " = " +str(i*j)+"\t" # print(string) # print("aaa",end="") # print("bbb") # for i in range(1,10): # for j in range(1,i+1): # print(str(j) + " * "+str(i) + " = " +str(i*j)+"\t",end="") # print("\n",end="") # for i in range(1,10): # for j in range(1,i+1): # # \n # print('alex', end='SB') # print('alex') # print('alex','haifeng','gangniang',sep='搞') # 这里面的数字两个组合 多少种不同样的,数字不重复的 # li = [1,2,3,4] # l =len(li) # for i in range(0,l-1): # for v in range(i+1,l): # print(li[i],li[v]) # for x in range(1,100//5): # for y in range(1,100//3): # for z in range(1,100): # if x + y + z == 100 and 5*x + 3*y + z/3 == 100: # print(x,y,z) # li = ['alex','eric',123] # li[2] = str(li[2]) # # # v = "_".join(li) # print(v) # tu = ('alex', 'eric', 'rain') # print(len(tu)) # print(tu[2]) # print(tu[1:]) # #step 为正 # print(tu[1:90]) # for elem in tu: # print(elem) # for idx in range(len(tu)): # print(idx) # for idx, elem in enumerate(tu, 10): # print(idx, elem) # tu =( # "alex", # [ # 11, # 22, # { # "k1":'v1', # "k2":["age","name"], # "k3":(11,22,33) # }, # 44 # ] # ) # tu[1][2]["k2"].append("") # nums = [2,7,11,15,1,8,7] # a =[] # for i in range(len(nums)): # for j in range(len(nums)): # if nums[i] + nums[j] ==9: # a.append((i,j,)) # print(a) # li = ["sdsdsd"] # print (len(li)) # li.append("dsad") # li.insert(0,"dsad") # li.remove("eric") # v = li.pop(1) # print(li,v) # # v = li.reverse() # for i in range(len(li)): # print(i) # for i,q in enumerate(li,100): # print(i,q) # for i in li: # print(i) # user_list = [ # ] # for i in range(1,302): # temp = {'name': 'alex'+str(i), 'email': 'alex@lve.com' + str(i), 'pwd': 'pwd'+str(i)} # user_list.append(temp) # # while True: # # 每页显示10条数据 # s = input("请输入1,2,3-31页码:") # s = int(s) # # user_list[0,10] 1 # # user_list[10,20] 2 # # user_list[20,30] 3 # start = (s-1) * 10 # end = s * 10 # result = user_list[start: end] # for item in result: # print(item,type(item))