基本数据结构的python实现 队列

队列：
与堆栈类似，通过python的列表类型来实现，参考 help(list)
shoplist=['apple','mango','carrot','banana']
print 'I have',len(shoplist),'items to purchase'
print 'these items are:'
for item in shoplist:
print item,
shoplist.append('rice')
print 'my shopping list is now', shoplist
shoplist.sort()
print 'Sorted shopping list is',shoplist
olditem=shoplist[0]
del shoplist[0]
print 'I bought the',olditem
print 'My shopping list is now',shoplist