Python：has_key，我想用if语句打印key的值

Question

could you please help me with this.

I want to print the value of the key with if statement. it is have one OR other value if it is not, but not for one, for all.

my try:

wp = {'tomatos': , 'patotoes': , 'milk':0.5'cheese':, 'eggs':0.25,'meat':2}
x= ' item is not available in this store'

how I can make my output like this?

tomatos item is not available in this store.

patotoes item is not available in this store.

milk 0.5

cheese item is not available in this store.

eggs 0.25

meat 2

thats mean if any Item in the list dont have price, print x infront of it, and for others print the price shown.

Answer 1

There are tons of ways to do what you are asking but the below would work:

wp = { 'tomatos': None,
       'patotoes': None ,
       'milk':0.5,
       'cheese': None, 
       'eggs':0.25,
       'meat':2}
x= ' item is not available in this store'

for k,v in wp.items():
   print "%s%s" % (k, (v if v is not None else x))

Please not the changes to wp .

Answer 2

Use the fact that the 'get' method of a dictionary returns None (by default) for a key that's not in the dictionary.

itemPrices = { 'milk' : 0.5, 'eggs' : 0.25, 'meat' : 2.0 }
sorry = 'Sorry, %s is not available in this store.'

for itemName in ('milk', 'potatos', 'eggs'):
    price = itemPrices.get(itemName)
    if price is None:
        print sorry % itemName
    else:
        print itemName, price