内置函数的使用

 1 li = [233, 43, 43, 3, 4, 2, 2, 2, 1, 2, 2, 3, 3, 4]
 2 
 3 # 最大值
 4 res = max(li)
 5 print(res)                     #233
 6 
 7 # 最小值
 8 res = min(li)
 9 print(res)                   # 1
10 
11 # 求和
12 res = sum(li)
13 print(res)                # 347

 1 # enumerate:同时获取序列的索引（下标）和值
 2 li = [2, 3, 42]
 3 res = enumerate(li)
 4 print(res)                # <enumerate object at 0x0000000002501E58>
 5 for i in res:
 6     print(i)              # (0, 2) /(1, 3)/(2, 42)
 7 
 8 # eval:识别字符串中有效的python表达式(可以看作把“”去掉),把str1转化成字典，把str2转化成列表
 9 
10 str1 = "{‘a‘:11,‘b‘:22}"
11 str2 = "[11,22,33,44]"
12 
13 dic = eval(str1)
14 print(dic, type(dic))      # {‘a‘: 11, ‘b‘: 22} <class ‘dict‘>
15 
16 li = eval(str2)
17 print(li, type(li))        # [11, 22, 33, 44] <class ‘list‘>
18 
19 a = 1000
20 b = 10
21 s1 = ‘a>b‘
22 print(s1, eval(s1))       # a>b     True 
23 
24 s2 = "print(‘python26‘)"
25 eval(s2)                  # python26
26 
27 # zip:聚合打包,长短不一样，取最短
28 # 注意点:zip打包之后返回的数据，只能使用一次
29 li = [1, 2, 3, 4]
30 li2 = [11, 22, 33]
31 
32 res = zip(li, li2)
33 
34 print(dict(res))        # {1: 11, 2: 22, 3: 33}
35 print(list(res))        # []