python 练习题

#!/usr/bin/python
books=[
        {"name":"abc","price":23.3,"store":u"xinhu"},
        {"name":"win","price":12.3,"store":"kk"},
        {"name":"kk","price":11,"store":"koko"},
        {"name":"linux","price":0.3,"store":"yamx"},                                                                                                          
]
res = min(item[x] for item in books for x in item if "price" == x)
print res