python - NameError : name 'form' is not defined (Python3)

Question

基本上，main方法接受用户输入，对其进行检查，如果用户未输入first，则调用quit方法。
first方法检查输入的第一部分，并根据用户输入的内容调用其他方法之一。这就是我得到错误的地方；例如，当first方法调用form方法时，出现了NameError: name 'form' is not defined异常。我对此感到有些困惑，因为我已经定义了每个方法，而且它们的拼写都正确，而且当我调用quit方法时，它也可以很好地工作。

主要方法:

if __name__ == '__main__':
        for line in sys.stdin:
                s = line.strip()
                if not s: break
                if (str(s) == "quit"): quit()
                elif (str(s) == "quit") == False:
                        a = s.split()
                        print(a)
                        if (len(a) is 2): first(a)
                        elif (len(a) is 3): first(a)
                        else: print("Invalid Input. Please Re-enter.")

第一种方法:

def first(a = list()):
        word = a[0]

        if word == "ls":
                ls(a[1])           
        elif word == "format":
                form(a[1])
        elif word == "reconnect":
                reconnect(a[1])
        elif word == "mkfile":
                mkfile(a[1])
        elif word == "mkdir":
                mkdir(a[1])
        elif word == "append":
                append(a[1], a[2])                               
        elif word == "delfile":
                delfile(a[1])
        elif word == "deldir":
                deldir(a[1])
        else:
                print("Invalid Prompt. Please Re-enter.")

其他方法(这些都是从第一个方法调用的):

def reconnect(one = ""):
        print("Reconnect")

def ls(one = ""):
        print("list")

def mkfile(one = ""):
        print("make file")

def mkdir(one = ""):
        print("make drive")

def append(one = "", two = ""):
        print("append")

def form(one = ""):
        print("format " + one)

def delfile(one = ""):
        print("delete file")

def deldir(one = ""):
        print("delete directory")

def quit():
        print("quit")
        sys.exit(0)

Answer 1

该错误是由于

    elif word == "format":
            form(a[1])

python基本上不知道什么形式。

让我给你演示:

gaf@$[09:21:56]~> python
Python 2.7.6 (default, Jun 22 2015, 17:58:13)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> form()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'form' is not defined
>>>

有两种方法

>>> def form():
...     pass
...
>>> form()
>>> form
<function form at 0x7f49d7f38a28>
>>>

或使用以下方法将其导入一些库

import 

命令

订单也很重要

try:
    form()
except NameError:
    print('Oops name error raise above')


def form():
    print('form foo is called')

try:
    form()
except NameError:
    print('Oops name error raise below')

会给你

/home/gaf/dashboard/bin/python /home/gaf/PycharmProjects/dashboard/test.py
Oops name error raise above
form foo is called

Process finished with exit code 0

附言
看看pep8
您的代码很乱％)
但不用担心每个人对母语的处理