【Python练习】利用列表List构建栈和队列
栈
栈是一个后进先出（LIFO）的数据结构，通常具有两个基本方法 push和pop，push负责将新元素添加到栈尾，pop负责将栈尾的元素删除。
#!/usr/bin/env python
""
stack = []
def push():
stack.append(raw_input('Enter new string :').strip())
def pop():
if len(stack) == 0:
print 'Cannot pop from an empty stack!'
else:
print 'Removed [', `stack.pop()` , ']'
def viewStack():
print stack #
CMDs = {'u':push, 'o':pop, 'v':viewStack}
def showMenu():
pr = """
p(U)sh
p(O)p
(V)iew
(Q)uit
Enter choice : """
while True:
while True:
try:
choice = raw_input('pr').strip().lower()
except (EOFError, KeyboardInterrupt,IndexError ):
choice = 'q'
print '\nYou picked :[%s]'% choice
if choice not in 'uovq':
print 'Invalid option,try again'
else:
break
if choice == 'q':
break
else:
CMDs()
if __name__ == '__main__':
showMenu()
队列
队列是一个先进先出（FIFO）的数据结构，通常具有两个基本方法 push和pop，en负责将新元素添加到队列尾部，de负责将队列首部的元素删除。
#!/usr/bin/env python
""
queue = []
def en():
queue.append(raw_input('Enter new string :').strip())
def de():
if len(queue) == 0:
print 'Cannot delete from an empty queue!'
else:
print 'Removed [', `queue.pop(0)` , ']'
def viewQueue():
print queue
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