初学python一个细小的问题

[what911]

#!/user/bin/env python
stack=[]
def pushit ():
stack.append(input('Enter New string:').strip())
def popit ():
if len(stack)==0:
print('Can not pop from an empty stack!')
else:
print('Removes[',stack.pop(),']')
def viewstack():
print (stack)
CMDs={'u':pushit,'o':popit,'v':viewstack}
def showmenu():
pr='''
p(U)sh
p(O)p
(V)iew
(Q)uit

Enter choice:'''
while 1>0:
while 1>0:
try:
choice=input(pr).strip()[0].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
CMDs[choice]()
if _name_=='_main_':
showmenu()
这样,返回Traceback (most recent call last):
File "E:/Python/菜单驱动.py", line 24, in <module>
choice=input(pr).strip()[0].lower()
NameError: name 'pr' is not defined
请教,怎么改?

[Rlay_2]

#!/user/bin/env python
stack = []
def pushit():
    stack.append(raw_input('Enter New string:').strip())

def popit():
    if len(stack) == 0:
        print('Can not pop from an empty stack!')
    else:
        print('Removes[', stack.pop(), ']')

def viewstack():
    print (stack)
    
CMDs = {'u':pushit, 'o':popit, 'v':viewstack}

def showmenu():
    pr = '''
p(U)sh
p(O)p
(V)iew
(Q)uit

Enter choice:'''
    while 1 > 0:
        while 1 > 0:
            try:
                choice = raw_input(pr).strip()[0].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
        CMDs[choice]()
if __name__ == '__main__':
    showmenu()

[what911]

[Quote=引用 1 楼 的回复:]

Python code

#!/user/bin/env python
stack = []
def pushit():
stack.append(raw_input('Enter New string:').strip())

def popit():
if len(stack) == 0:
print('Can not pop from an empty s……
[/Quote]
嗯.是缩进问题.但是我改了while缩进之后提示NameError: name '_name_' is not defined

[what911]

[Quote=引用 1 楼 的回复:]

Python code

#!/user/bin/env python
stack = []
def pushit():
stack.append(raw_input('Enter New string:').strip())

def popit():
if len(stack) == 0:
print('Can not pop from an empty s……
[/Quote]
双下滑...搞定.

[悠亮仔]

谢了，缩进一直是个问题，python核心编程电子版例子上的缩进一点都不规范

[tiefeiying]

showmen函数下面包括while那段，被坑的好惨