# a=[i for i in range(10000)]
# print(a)
# a=[i for i in range(0,10000,2)]
# print(a)
# a=[i for i in range(10000) if i%2==0 ]
# print(a)
# a=[i for i in range(200,501) if i%5==0 or i%7==0]
# print(a)
# a=[[1,2,3],[4,5,6],[7,8,9]]
# b=[a[i][1] for i in range(len(a))]
# print(b)
# b=[a[i][2] for i in range(len(a))]
# print(b)
# b=[a[i][i] for i in range(len(a))]
# print(b)
# b=[a[i][-i+2] for i in range(len(a))] #b=[a[i][-i-1}
# print(b)
# a=[[2*j+1+i for i in range(3)] for j in range(3)]
# print(a)
# a=[[3*j+1+i for i in range(3)] for j in range(3)]
# print(a)
# a=[[1*j+1+i for i in range(3)] for j in range(3)]
# print(a)
# a={1:20,3:40,5:60}
# b={v:k for k,v in a.items()}
# print(b)
# "zk"
# a={'a':30,'b':4,'c':21,'A':20,'B':22}
# b={k.lower():(a.get(k.lower(),0)+a.get(k.upper(),0)) for k in a.keys()}
# print(b)
# a='123'
# for i in a:
# print(i)
# a=[1,2,(14,5),'张三']
# for i in a:
# print(i)
# for i in range(2,20,3):
# print(i)
# a='123dko'
# for xb,v in enumerate(a): #枚举
# print(xb,v)
# a={'name':'张三','age':23,'address':'北京'}
# for i in a:
# print(i)
# print()
# for i in a.keys():
# print(i)
# for j in a.values():
# print(j)
# print()
# for k in a.items():
# print(k)
# a=[1,2,5,3,2,1,62,4,2]
# b=set(a)
# for i in b:
# print(i,'出现%d次'%(a.count(i)))