

'''
string example
a="ssss,fdsfds,ss"

print(a)
print(len(a))
print(a.split(","))

as long as risks are managed that some prominent economist thinks;
i feel fear about the intension of trade war between america and china ,if
if we slip into trade war, all of us will be dameged badly,


'''
'''
 about list implentment
 author:jackwu
'''
'''
ex=list();
ex.append("xxx")
ex.append("xxx")
ex.append("xxx")
ex.append("xxx")

#print(len(ex))
#ex.pop()
#print(ex)
#list initializer
# others call it list producer
#it's easy to use

a=[x*x for x in range(10) if x &0x1 ==0]


print(a)
print(a.pop())


#b=[s.upper() for s in ex]
#print(b)


#print(a)

for i in ex:
    print(i)

'''



"""
map

"""
'''
a={"name":"jhackwu","age":23};
print(a)

a["xxx"]=4;
a["xxx"]=5;

for (i,j) in a.items():
    print (i,j)

print(a)
print(len(a))
#print(a.popitem())

for (i,j) in enumerate(a):
    print(i,j)
    
'''

a=list((11,2,3,4,));
print(a)

for i,j in enumerate(a):
    print(i,j)






