Nation_River={'YangtzeRiver':'China','Nile':'Egypt','Yellow_River':'China','Amazon':'American'}
for key,value in Nation_River.items(): #便利dict中的键—值对
print('\nkey:'+key)
print('\nvalue:'+value)
print('\nThe '+ key +' runs through '+value+'.')
for river in Nation_River.keys(): #便利dict中的键
print('river:'+river)
for nation in Nation_River.values(): #便利dict中的值
print('nation:'+nation)
for nation in set(Nation_River.values()): #过滤dict中重复的值
print('\nnation:'+nation)