ys={'春':'养心','夏':'养肝','秋':'养肺','冬':'养肾'}
ys['春']='养肝'
ys['夏']='养心'
print(ys)

ys={'春':'养心','夏':'养肝','秋':'养肺','冬':'养肾'}
ys['春']=ys['夏']
Ys['夏']=ys['春']
print(ys)

ys={'春':'养心','夏':'养肝','秋':'养肺','冬':'养肾'}
ys['夏']=ys.pop('春')
ys['春']=ys.pop('夏')
print(ys)

ys={'春':'养心','夏':'养肝','秋':'养肺','冬':'养肾'}
ys['夏']=ys.pop('春')
print(ys)