for value in x.values():语句是将所有值都遍历.所以输出了3遍
举个例子:
x={'math':201,'chemist':205,'english':203,'chinese':202}
for k in x.keys():
value=x[(k)]
print((str(value)),':',k)
这样就只输出一遍
升序可以用冒泡排序
x={'math':200,
'chinese':202,
'english':203,
}
x['math']=201
x['chemist']=205
for key,value in sorted(x.items()):
print(f'{value}:{key}')